I've been using a fridge w/thermostat to control fermentation temperature for ~6 months now & have recently started dual-purposing the fridge for a keg as well. Since serving & fermentation temperatures don't match I can't run them both in the same fridge simultaneously.
In order to maximise beer drinking time, I'd like to aim to regulate fermentation temperatures for the shortest time possible. At what part of the fermentation process (or any other process really) is temperature control most valuable? The first hours while yeast gains a foothold? Conditioning? The whole lot? How much ambient temperature fluctuation do I really need to care about?