I have my Stax L700 Mk2 for sale, my first entry into electrostatic headphones. I estimate that I had listened to them for less than 10 hours in total. Whenever I didn't use them, I had them stored properly - I used the included plastic bag - plastic container/bag is recommended in general...or keeping them somewhere closed - a cabinet, drawer, etc, where dust doesn't circulate much.

I gained a lot of actual sonic respect (if anything like that even exists) for the sound of electrostats, but I found that I am way too gone into my Senn HD800 - those are not perfect and not everyone's cup of tea, but I just can't go back from feeling like I am listening to my desk speaker setup, but with headphones on my head.
With that being said, damn these sound energetic and lively. I believe, on top of everything, anyone enjoying definition of musical instruments will fall in love. I can't promise that, though, you'll have to try for yourselves.
And they produce...bass? I wasn't expecting that at all, but I was very much surprised.
Anyway...sorry, I couldn't help it, I had to give some of my own impressions.

They look awesome, they show no signs of use. I used them with very recent Topping EHA5 amplified/energizer which has gotten a lot of praise for what an astonishing power and transparent amplification it can provide for a fraction of the price of some of original Stax energizers and "sound" even better than them. I will be selling it in another ad (check my other offers).

Warranty is included, the headphones are under a warranty until March 25th 2025. They were purchased from an official distributor for Stax in Europe.