ipad 4 - Should i keep charging after 100% ?

Should i keep my ipad 4 plug in even after 100%, just the way i do for laptop? As i charge my ipad twice daily from 40%, as my heavy usage is mainly on games that i play through wifi daily. and some streaming on it through my desktop pc.

right now i dont charge after 100% at all, but would it be alright and not damage my battery life!

And how long will my ipad 4 battery life will last and how to confirm how many cycle is left?