Interesting thread, I am a relative newb but am on my third successful brew and this subject was something I pondered a lot over the last few months.
I became obsessed with the fermentation activity early on with my first brew (cider from our apple trees), as it was a seat of the pants experiment.
I was at the point of nudging it along with Wilko's yeast nutrient when it appeared to slow up within the first week of the experience.
I am not sure if our water here affects the process, this is something I'd be interested in learning more about, but it's an issue niggling me, as we have hard water.
My Woodfordes Wherry went well but I did pop a teaspoon of yeast nutrient in that just over half way through the fermentation period, it looked like it was stalling but picked up well again after that.
On my 3rd Tiny Rebel 'Cwtch' brew I began wrapping a jacket around the fermentation bucket if it looked like it was dropping below 20 degrees in the room on colder days. I also nudged that one along with nutrient in the same way as the Wherry, meaning it seemed to reach it's brewed gravity a day or so earlier than on the instructions.
I also now have stick on thermometers for my fermentation vessels and I bought 2 further thermometers off eBay so I can track inside and outside temps.
We have underfloor heating via a ground source heat pump, which creates fairly even and stable environmental conditions, my son's room is vacant at present, as he's off at uni, so it's perfect for brewing.
It holds an almost constant 19 to 20 degrees, so the brew temp hangs between 21 and 22 degrees. Circa 2 degrees above the room temp.
Good luck with this, keep us posted.