I think that always better to sell your mining coins if you are not in China, taxes is very hard to pay right now and better to have enough money for it.
I sold use the bitcoin I mine to pay for the mining cost. I will hold most of the coin whenever possible as the price will rise in the future.
What you are doing is a very profitable practice, mining would give you income if you are not going to sell it right away and we have witness in the past that most of the long time holders are making fortune of bitcoin. I can see this will happen also to you if you will continue to do the right practice.