I use enough power to get the QSO done with without a large number of retransmissions. Using less power but needing to repeat the transmission 5 times increases the S/N ratio for everyone. I've got no problems with throwing out 400W on 160m on FT8. Now if I get a report back that is +30dB or something, sure I'm going to turn it down, but often at higher power levels, I'm getting a nearly matching report back as a result. (Also I try really hard to make sure I'm not stomping on someone).