water heater flex question

I installed 12" ss braided flex lines on my water heater, and the directions say 'hand tight plus 1/4 turn'. I wrapped my fist around the fitting, and turned by hand until they stopped. No leaks, but should I do the extra 1/4 turn w/wrench? Don't want to distort the rubber washer too much, or damage the thread (it's 3/4"npt), but I also don't want it to be too loose and leak as the rubber gasket ages. Thanks, I apologize if this is a dumb question, but I don't work with this stuff all the time, and I am not sure. Thanks again.

connections

My rule is to tighten them as tight as they will go, NOT just a 1/4 turn past hand tight. How do THEY know how tight YOU can turn them by hand?

Agree with hj on this...I have always tightened them down...not the 1/4 turn past hand tight...I used to argue with another plumber about that until he flooded a home and had an Ins. claim...funny he didn't argue with me any more...