In some games, it feels out of place and it causes you both problems and grief. In other games, it feels great and fits right in!

Some of my examples...

I love durability system in diablo 2.

I hate durability system in witcher 3.

I love durability system in VtmR (vampire the masquerade Redemption).

I hate durability system in "Symphony".

Imagine this: Hard as a rougelike with several instant death traps and a slightly obtuse level system, no actual skills, and there's no option to repair anything.
Go on and give some detail for those of us who haven't played, if you'd like.
But what if you're forced to backtrack to somewhere or you're doing quest cleanup and your ubersword breaks on a goblin and now all you've got is a tree branch?
So basically, if there's magic or things akin to magic, durability is off the table for you. Which I do agree with. It's baffling to be in a fantasy world where it turns out your empathic blade can't be reforged in a wizards tower because nobody bothered to set up a magiforge.
That sounds like something I'd like. A sensible option, really. Of course, one would presume that up to a degree, there comes a point where equipment is not to be repaired, but instead sold or exchanged for better equipment.
Then it looks like you wouldn't enjoy Breath of the Wild going though weapons like a magician goes though playing cards.

^ This is key. Either the game is designed to give you sufficient resources so that you don't get stuck like that, or otherwise, game mechanics make sure even the tree branch could be deadly in the right hands.

I'll come up with examples... soon.

Well, the tree branch does 1d3 damage which is useless in areas you'll be returning to, where the opposition has 100-1000 HP, breaks in about 5 hits, and is hard to get rid of due to a poorly designed interface.

Some other interesting cases of durability:

Zelda: Ocarina of Time has durability in a couple instances. First, there's the Deku Stick, which is stronger than the Kokiri Sword (and, like the Kokiri Sword, is available very early and usable by Child Link), but which breaks aftter one hit. You can carry up to 10 of them, and certain enemies can drop them (specifically, Deku Flowers). They also exist in Majora's Mask. The other example is the Giant's Knife, which is stronger than the Master Sword, but breaks after 3 hits; this one is really just there as a trap, and to hint that there might be a way to get an unbreakable weapon with this power.

Zelda: Majora's Mask has, in addition to Deku Sticks, the Razor Sword, which replaces your Kokiri Sword, but will turn back into the Kokiri Sword after a certain number of hits (or if you restart time). I think this would have been an interesting mechanic if the Gilded Sword didn't exist.

Now, for an entirely different situation:

What do you think of weapon durability in games where you are not expected to use weapons most of the time? For example, how about a platformer where you can kill enemies by jumping on them, but where you can occasionally find limited use weapons to use as a weapon? Or, for that matter, how about weapon durability in a game where you are not meant to be killing most of the enemies you encounter? (Let's assume here that every situation where you have to kill an enemy (like a boss) either doesn't require weapons or has an infinite number of the needed weapon spawn during the fight.)

Diablo 2. You get color notification, depending on how severely damaged your equipment is. Gear which isn't too fast or easy to break, unless you are playing hell difficulty and are melee oriented. You get early warning, this way and what's better, when something breaks, it doesn't disappears (only its bonuses do), it is still present and with one repair, it is as good as new.

Witcher 3. I prefer the style of 1 and 2, who didn't have any (durability system). Witcher feels out of place with something like that. You aren't free anymore (especially like in 1), to get lost adventuring and exploring freely in a carefree manner... On the contrary, you have to seek NPCs all the time, for selling this, repairing that, etc. They even get a reduced performance, once damaged too much. I didn't try breaking them, so i don't know what happens in that case, but still, i didn't like that, much. I didn't like the different merchants giving you different prices and all of them having limited money, less...

Vampire the Masquerade Redemption, doesn't have a durability system. Instead, it has item types. "Rusty" medieval weaponry, with lowered stats. Normal ones, with decent stats. Then there are the Fine and Exquisite varieties, which give better stats and even, change the appearance of the item's icon in inventory, or its graphical representation in the environment, wielded by the characters' hands!

Symphony, is a GOG game, of the "insert your music collection" variety and pilot something plus shoot with it, on the rhythm! You unlock different turrets with different weapons and power, but they have a durability system, as well. The more damage you sustain throughout the tracks, the lower it gets. I don't remember now what are the consequences of it being lowered, but i simply hated it. Especially on the rare variety of turrets.

Really depends on the design of the game. If it's "die and retry" friendly ala Rogue Legacy, that may be fine too.

Frankly, I'd take "no repairs" over "it's really just a hack-n-slash where you kill anything that moves, but you still need to get back in town and pay the blacksmith to fix your sword... it's just an additional item on your grocery list" any day. "no repairs" may add at least some value to the game by forcing you to pick your fights more carefully.

I hate weapons that break. On the other hand, you can also say "ammo is durability by another name". Which makes sense from a mechanical perspective? I guess that I appreciate a game like DOOM much more than Breath of the Wild, since I don't have to go into inventory menus and fiddle around.

Interestingly enough, two game series I mentioned, Fire Emblem and SaGa, take that approach the other way around; there is no ammunition in these games, but bows (and in SaGa, guns), like other weapons, do have finite durability.

Of course, it helps that, in both series, the remaining number of uses is displayed right by the item's name in all menus, so you don't have to do any work to check the remaining number of uses. Also, when you attack, you choose any weapon you have equipped, and you can equip as many weapons as you have space (but, of course, only actually use one at a time).

Also, these games go even further: Durability also replaces MP in these games, as spellbooks can be used to cast their spells constanty until their durability runs out, and they're durable enough to be used as primary weapons (especially since, in Fire Emblem, most casters *can't* use physical attacks).

Edit: Another interesting case, that perhaps I will mention later, is Romancing SaGa: Minstrel Song, where durability is more of an opt-in thing.

I hate durability systems, since they almost never add a worthwhile element to the game and are just tedious.

Take Diablo 2 for example: You're swimming in gold pretty soon and from that point on repairing your weapons is just another boring step in your town routine until you get back to the front. It doesn't add to the immersion and it doesn't makes me making meaningful choices about my equip.

Yes and no. Firstly, it makes sense to have this systems, as there are quite a few unique weapons and armors in the game, which are given as quest rewards or found in strange places. It would be bad design to make the player jump though all the hoops getting one of them, only to make them get destroyed shortly later, so you tend to try to get those and then stick with them.

For the more common weapons and armors dropped by mobs, you have the option to either use them to repair your own gear (which will destroy them) or sell them for caps. For 'normal' weapons, you can also add modifications to make them better, and again, if you have worked hard on finding a weapon you like, and modified it to the hilt, it makes sense to be allowed to keep it. (for example, instead of one of the unique shotguns, I use a modified riot shotgun for close combat now, as it use very little AP but still packs quite a punch)

I think it is a system which works very well.

From a Skelemancer's playthough, what I understand is that Diablo is about shopping/gambling and that it is very zen.
Also Doom doesn't even bother with reloading and gives you a peashooter with unlimited ammo. Breath of the Wild gives you no such mercy. You run out of weapons, your peashooter is either a leaf or a branch.

Romancing SaGa: Minstrel Song has an interesting approach to weapon durability (which the game calls DP). Specifically:
* Basic attacks do not consume DP.
* More advanced attacks do consume DP, but if you are using a weapon appropriate to your class, you can reduce the DP cost based off your class level. It is possible to reduce the cost of most skills to 0, and for some weapons, can modify the weapon to (in combination with your class) reduce the cost of all skills with that weapon to 0. (There is a minor cost to power, however.) (Note that classes are optional in this game, but getting level 1 or 2 in a class is extremely cheap and quite helpful.)
* Going to the inn will repair unforged weapons. If you have used materials to forge your weapon, however, you will need to re-forge it to repair it. (This is where the opt-in aspect really lies.)
* Skills that do not use a weapon, or those that use certain special weapons that don't have DP, use LP instead (but the cost can still be reduced). LP recovers at the inn, but it also drops when you reach 0 HP, and if it reaches 0, the character is removed from the party (so you have to re-recruit the character). If the main character reaches 0 LP, it's game over.

Anyway, I still want to know what people think of weapon durability in games like mario-style platformers (that is, platformers where your main attack isn't with a weapon, and weapons are just special power-ups that you occasionally find).

No platformers are coming to mind that have a durability mechanic. In Mario, you run about with reckless abandon until you bump something with a harmful property, in which case you lose the power up.

But a topic for another thread is why bother with collision damage in the age where we have more than enough technology to animate a basic attack animation.

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