We have been living aboard for over twenty years in a variety of boats and in different countries. We started out living aboard a 27 foot sailboat in Canada and believe me there is no way you can store everything you need to survive in that climate on a 27 foot boat. We were lucky because our marina allowed us to put up a tool shed for storage on their grounds. We paid them a small fee yearly fee and it worked out well.
When we set off cruising (still on the 27 foot boat) we never missed anything in that shed... but then we didn't need all our winter gear
, Manny wasn't working and we didn't need to do any big repairs on the boat.
Now we are living on a 30 foot boat in a small marina on the Red Sea. We have two dock boxes and we have a few boxes stored in town. Most of our storage is for Manny as he works off our boat. He does marine refrigeration and air conditioning and electrical work and needs space for tanks of gas, welder, spare parts etc. If we had a bigger boat, we probably could store his tools on board. We also have an old car that is packed with his tools too. One day soon we'll go cruising again and we'll have to find a better solution.
Other than Manny's tools maybe 4 boxes are for important papers (which unfortunately we are required to keep), and a few small memories from our childhoods. The thing about storage is that no matter what size of a storage unit you get, you always seem to fill it up...well that's our experience anyhow.
Manny and Robyn