“If you are early, then you are on time. If you are on time, you are late.”
This is the cliche that I have lived by for so long and I think it should be a motto that many musicians should live by too. Some people may potentially see your promptness or earlybird-ness as being a brown-noser, but if you want to stand out among the rest of the guitarists, drummers, bassists, etc., and want to become mroe desirable as a musician, then this is one small statement you can make.
I am not trying to be an elitist or pretend like I know it all, but it always bothered me when musicians, stumble into a rehearsal, and disrupt the flow of things. That’s it! Promptness prevents the disruption of flow. Yes, there are things that happen during rehearsal too, that are unavoidable, but you do not want to become the conspirator of ruin for your band, gig, and bandmates.
Overall, I believe this 3rd thought should be practiced in all instances of life, regardless of the venue or situation.