My commute is about 27 miles round trip. Takes about 1 hour each way. Am not racing.
Mostly bike path along the beach.
Bike is a surly LHT
I use two grocery panniers (one for essential tools on the bottom, and the rest of that bag is for work clothes and materials). The second grocery pannier is for any farmer's market stuff or grocery stuff on the way home.
Have been doing it for three years.