Pro tip: flip your baseboard miters before you cut them, not after
For the first 5 years I cut all my inside miters the standard way, then fought with caulk and wood filler to hide the gaps. Last month on a ranch in Boise I tried flipping the board upside down on the saw so the face sits flat against the fence. Cuts came out tight on the first try for all 14 corners. No more shimming or recutting. Has anyone else switched to this method and found it helps with uneven walls too?
I gotta push back on flipping the board before you cut it. That trick works fine when your walls are square and your floor is level, but on older houses where nothing is plumb it messes with your angle. When you flip the piece you are cutting the miter backwards from how it sits on the wall, so if your saw is off by even a hair it shows up twice as bad. I have done this for years on remodels and the standard way with the face against the fence gives me a better feel for the actual corner. Plus with uneven walls you still gotta cope or shim no matter which way you cut it, so flipping just adds another variable you gotta watch.