We depend on lists. Wife has the food and kitchen list, I have the camping, RV etc list. We also have acquired duplicates of most of the things we use in both the RV and the house, so only the first trip of the year do we have to bring everything out.
We took a short trip near home for our first trip to find out what we needed and didn't have on our lists. The lists are continuously updated as our needs change.
If you forget things, not a big deal. There is always a Walmart around.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory