Powering up is always a good idea. However, some are speculating with a higher SBD price which would give you much more SP compared to now. But we don't know that. You could just buy 1 Steem every day (or replace the number with any other). That increases your amount gradually and you spread the volatility.
But you should certainly reinvest some of your earnings into SP in one way or another.
Thank you. I'll decide on an amount that makes sense with my current activity.