Heya,
I just keep a few headphones. I went the route where you get a more than capable amplifier for your headphone collection so that you can try other headphones in the future that may have different requirements (for me Little Dot MKIII). Have a decent enough DAC to send the signal to it (for me Forte, Vivid V1 Tech). Then simply collect headphones that have different sound signatures that meet your taste for what you're listening to. For example, I have some open-air cans for home listening, games and movies. One fairly neutral and one fairly bassy (for me HD580, DT990). I also have some closed-back headphones for electronic music and for going out, walking, work, school, to minimize leak and have better bass response for the genres I put through them (for me DT770 Pro, Ultrasone 900 Pro).
And I'm still itching to pick up some Grados, AKG's and some other ones I don't currently own (but have tried) just to sometimes switch it up. Some days I just want to listen to vocals and others I want crunchy house music. Different phones for different listening experiences.
Also, I try a lot of headphones, yet I don't have a place near me that has them to try and I haven't been to a big meet yet (though I want to next time). You do risk a lot buying something you've not listened to. And frankly, reviews can make something seem great or seem bad. A lot of people review the M50 as great. I don't like them. Someone might say some great things about a headphone, or bad things, but it's your ears that will reveal the truth. So you just have to listen to a set of headphones. It's difficult if you don't have access. And that's why I buy them on Amazon. Their return policy is no-questions. I just get them, try them for a month, and send them back for a full refund. I keep the ones I really like. Otherwise, I can at least say I listened to them for a few weeks. I do this to test out headphones. You're not losing money to do it (sometimes a bit on shipping perhaps, but they reimburse for some shipping too which is nice). I feel like I'm `leasing' headphones in a sense, since I keep rotating a pair that I have at home, send it back, get another pair, etc. And Amazon doesn't care how often you do it. Their policy is simple. You just click a button, print the RMA, send it back, get a refund with no questions asked, and go back to buying. Probably sound like a lobbyist or something, but I can't stress enough to people that don't have access to headphones for testing that you can do a method like this to try something without a gamble. Just make sure you buy from Amazon and not a store on Amazon (big difference in return policy).
Very best,