A classic case of how pleather ear pads can be short lived is through a headphone many recommend to newcomers- the ATH-M50. These have pleather pads, so as such, they make you sweat after extended periods of time, and, unless taken care of, can crack within a few months of purchase. There are some velour alternatives that will fit the M50, one of which is the most common(it was a DT-something headphone. I do remember reading about it at some point, but I don't remember the exact name. I think it was 250? If someone can confirm this in a post that'd be great) that is around $30(USD), and recently, is somewhat difficult to find, so it isn't very practical to get.
However, this could save you a lot of new $10 pad purchases if you choose to simply buy new M50 pads. But, the reason most will have to get new ones is a common problem: they don't take care of them! The non-care will cause them to get hard, and eventually, crack, which is what will normally force most to get new pads.
So, what causes this cracking? There are a few common reasons:
1. Sweating when wearing for long periods of time/in a hot area
2. Not using leather protector
3. The headband isn't stretched(this puts extra pressure on the pads, makes you sweat easier)
Now, these can all be helped to some effect.
If your sweating can't be helped, like if your environment has to be warm or it can't be helped, at someplace like work, take them off about every hour and take a break for five minutes or so. Be sure to wipe them off on your pants or something similar before you put them back on. Wiping them off once in a while is a good idea anyway, but especially in warm environments.
Not using leather protector can be stopped simply by, well, using leather protector! Most "finished leather" protectors will work; just spray it, spread it, whatever it needs you to do, onto the pads, and it'll work! It'll protect against the extra force if you headband isn't stretched and also protects against a bit of sweat.
Stretch the headband! Typically, adjusting the headphone to your comfort-size and stretching it across the box it comes in over-night will stretch it quite well. Make sure to stretch it across the longer-length part of the box. If it won't fit on that one, obviously, use the other side. It isn't a good idea to use just one box, however; if you get some smaller on-ear 'phones and you try and stretch it on a over-ear 'phones' box, it'll stretch too much and they'll be too big for your head! This also applies as a general headphone wellbeing tip and should help the comfort a bit!
... and there you have it! My pleather care guide! Hopefully this helps anyone having a bit of troubles with the doomed pleather ear pads. Obviously, velour makes a much better headphone pad, but some don't have velour pads that fit it(or even pads that fit from a different headphone), so the pleather pads are a non-option.
If you have any questions, feel free to ask. And, does anyone know what DT headphone's pads fit the M50? I really want to say the DT250's pads are what fit, but I'm not certain.