does anyone ferment with the hydrometer in the carboy?

[Aub]

I've found that with experience, I can depend less on measurement and monitoring. After you've had a few batches with a particular recipe or yeast behave a certain way at a few different temps, it's pretty easy to extrapolate and get very close. I still like to steal a sample, especially with a lager, to see how things are going, but I could run most batches from start to finish without any readings at this point.
Take notes and refer to them often.

Yeah, you can't beat experience, that's for sure.