An X2 battery is "good" for about 300 charge cycles. That may be extended if it is charged prior to reaching the point of the battery signaling it needs to be charged.
The X2 clearos I got back in July are still working well. I do clean them regularly, heavy , fairly light dry burn, and let them dry for a few days. The ones I got recently have all been disappointing performers. Either the inner silicon flat washer seal falls out making them prone to leaks or the coil goes open in less than a week or two at the most. There seems to have been a definite change in quality in this last batch.
Just my opinion, worth what you're paying for it. Your results and mileage may vary. No warranty or guaranty is expressed or implied.