A sturdy cotton bag needs to be used around 130 times to beat a single-use plastic bag on environmental impact, so the key is actually reusing it.
Keep a few bags by the door and one folded in your bag or car so one is always within reach.
Wash fabric bags regularly, because a dirty bag can carry bacteria from raw produce to other items.
Repair a torn handle instead of replacing the bag, and a well-made bag will serve you for years, not weeks.
The most sustainable bag is the one you actually remember to bring.