A lot of people never consider that accessories might have accessories of their own. For headphones, there are actually a lot you can do to improve them, ranging from physical modifications like changing the cable or making the cable detachable, to simply replacing parts of them with new or different parts.
More expensive headphones often have replacement parts available from the manufacturer. Ear pads, head bands, and other replacement parts can often be had by just looking at the manufacturer’s website. Just as an example, look at Bose and Sennheiser’s spare parts pages. You can often improve the usability of your headphones greatly by switching out parts that wear down every so often, and it’s definitely cheaper than buying new headphones.
Some companies also offer alternative parts for their gear. Examples include pleather, leather, or velour pads for headphones that come with only one of those. My Beyerdynamic DT-770 headphones came with velour pads, but I also have a pair of official leather pads that I got on the side. Various parts can have different properties, and I find that leather often offer better sound isolation, while velour is more comfortable.
The most popular budget offerings also often have replacement parts available. An example is the Koss Porta Pro headphones, which you can get packs of replacement foam cushions for. These tend to fall off quite a bit, and it amazes me how many people I see still wearing them after that happens, without getting replacements- likely because they’re not aware of them.
Even if you don’t have any headphones that have official parts available, all doesn’t have to be lost. Headphones are often more similar than manufacturers let on, and you can actually often use parts from other (and more expensive) headphones with the ones you have. I recently got a pair of AKG k518DJ headphones on a sale, and I immediately ordered a pair of velour replacement ear pads for the Sennheiser HD-25 to use with them. This particular combination is fairly popular in the headphone community, and it drastically improves the comfort of the AKGs. If you have a pair of headphones you like but wouldn’t mind a comfort upgrade for, looking around for replacement pads of the same approximate size is not a bad idea. Sometimes you can even find tips as to what combinations work online.
If ear buds and IEMs are more your style, you also have a few options. Comply has been making third party foam tips for IEMs for years, and have tips that fit a variety of IEMs. More companies have come onboard with making replacement tips now, including of course the manufacturers of IEMs themselves, and they’re normally not too hard to find. Another accessory type for IEMs is ear guides, like the ones from Phonak which I loved back when I actually used IEMs.
As someone who has been modding and adding accessories to headphones for years, I can assure you that it can make a big difference. I wouldn’t even have gotten the AKG k518DJs I mentioned if I didn’t know about the velour pad trick, as they’re not very comfortable without them. By getting those pads though, I ended up with a pair of good sounding, portable, and comfortable headphones, all without breaking the bank.