If you have funds for your mining operation and for your daily life and bills, then there is no harm in waiting for the next bull trend.  You will only regret if you sell your ETH at a loss when the possibility of the ETH market skyrocketing is pretty clear.

And if your budget is limited and not sufficient for your daily needs, then there is no other way but to sell them to fill the funds that you are needing for your daily expenses and monthly bills.