The battery inside the digital camera

I have a SONY digital camera, which uses rechargeable batteries (the batteries are about the size of a matchbox, but only half the thickness of a matchbox, quite thin).

However, since I don't use this digital camera for a long time, now after I fully charge the battery, I take it out and then after 3 months, I put the battery back into the digital camera to check if there is any power left. If there is no power, I will charge it again. This process repeats over and over again. Is this method without any problems?

Now, what I want to do is take out the battery and then keep it until I want to use it, at which point I'll charge it again. This could be after six months or even a year. Would this be okay?