I used to take a minimalist approach to vacations, managing to do without a lot of "stuff" on our trips. But we decided to try OL and now I get it! I enjoy having plenty of hangers (especially plastic ones to hang dry damp bathing suits), a toothbrush holder, a lighted vanity mirror to combat aging eyes and dim lighting at AKV, decent sized coffee mugs and cereal bowls (AKV again), power strips and extension cords for all of our electronics, a bathrobe, a small digital clock for the other side of the bed, etc. It's handy having plastic wrap, aluminum foil and leftover containers since we do fix a few meals each stay. We also keep a supply of coffee filters in our locker.
We also have lots of toiletries which occasionally need replenishing or recycling (I take stuff home when it's getting close to it's expiration date to use it up) so you do need to make a list at the end of each trip of the things you need to bring down next time to restock the locker.
There are two downsides to getting a locker. The first is that it takes longer to pack up at the end of a stay since you have to pack up the locker as well as your luggage. I find packing up very depressing so I delay as long as possible but with a locker, I need to get started earlier. The second is that if you used to take your luggage from the room on your own, you'll be using Bell Services now since you will have a heavy locker in addition to your bags. So factor in the cost of tips.