We have a year-round beach box which collects items we don't ordinarily use at home, but are handy once we get to our beach digs. Things like small propane canisters for our beach grill, queen sheets, common coffee filters which don't fit our machine, ghost crab lanterns, bug repellent with DEET etc.
When we get about 30 days out we begin to add little baggies of supplies. We'll do a baggie with 14 dishwasher tabs, another with 14 laundry pods, another with 14 dryer sheets, never run out, but never have more than a few leftover either. Refill the small bottle of dish soap, refill the soft soap dispensers, toss in a kitchen sponge, a roll of paper towels, half a package of napkins, 9pk of tp, kitchen towels, sharp knives, good cutting board, 1st aid kit, beach books, sunscreen etc.
Lastly we'll try to remember all the little things we have forgotten in the past. Things like bottle openers, lighters, grill tools, vitamins, medicines, salt, pepper, mustard, ketchup, things that you'd hate to buy a full package of for just one week.
The box helps in many ways. It helps with early onset beach anticipation, help keeps us out of grocery stores and checkout lines and on the beach, helps save money and spread out costs. We keep adding to it until the day comes, greatly reduces if not eliminates last minute running around and anxiety.
It's a good tradition.