On group rides with others to watch your bikes, fine; no lock necessary. If you’re solo, bring a lock. And don’t freelock. In my experience, the guy behind the counter of the 7-11/quickie mart etc. doesn’t care about you or your bike. If they let you bring it inside, awesome. I still lock mine. You should too.
Locks are cheap insurance against theft. Granted if they want it bad enough, a thief is gonna get your bike. I used to do a group ride that would finish at a patio bar/restaurant, and everyone used to laugh because I always brought my u-lock. Until 4 bikes got jacked not 10 feet from a group of roadies sitting on the patio. After that, no laughter, only questions about where to get a kryptonite and u-lock holster.
Many bike thieves are opportunists, not master criminals. I often see really nice crabon bikes outside coffee shops just leaned against the wall in ones or twos. The Dr. Evil part of me really wants new Zipps, but the human part of me goes inside and politely reminds the owners they really oughtta keep an eye on their bikes.
U-locks are relatively cheap(the Palmy retails about $35) especially compared to the $1000+ or so you’ve got invested in that commuter or high zoot roadie.
My Kryptonite Evo mini cost about $65. Not bad. Especially considering I’ve got about $4k in my road bike and $2k in my track bike.
And if you’re worried that the extra weight from that lock is gonna spoil your strava times, imagine how long that segment’s gonna take on foot.
Just my 2cents.
Oh, yeah- for me, I like water in my bottles and gels for food. For some reason bars, waffles etc. just come straight back up. I average 1-2 bottles for a 3-4 hour ride.