Here is a response I wrote in another thread just below this one not long ago to a similar question.
I can do quite a few sleight with both hands including the classic and finger palms among other concielments, because they are neccesary. But I find that it is best to learn sleights as you learn new tricks that require those sleights. That is when you will be the most ready to learn.
Kind of like how when you are learning guitar. You learn the chords as you learn to play the songs that require those chords, otherwise it will feel pointless to you.
So don't try to back thumb palm a coin in your left hand(for example) just for the sake of learning the sleight in both hands. Learn it when you come across a trick that requires you to back thumb palm a coin in your left hand and you will actually learn how to do it.
Well that's what works for me at least.
So basically learn the basic concealments in both hands but only learn more advanced conceaments and techinques in both hands if neccessary. Like my example for instance, I haven't come across a routine that requires me the back thumpalm a coin in my left hand so I haven't learned it in my left hand. If I do find a routine that I want to learn that requires it then I'll have an incentive (reason) to learn it and I will learn it.