He won’t be making his home on a ship, except on deployments and underway periods. While on long deployments, if he has a roommate, roommate looks after stuff. While roommate deploys, he does the same. Or, he might go very basic if living solo and put stuff in a storage unit while deployed, skip paying rent and dropping his personal property insurance coverage to reflect he is not renting with a need for liability coverage. Or, he rents a basic bedroom suite and living room set, and is easily done with it when it’s time to move. I was at a 6-month school one time between duty stations, found a nice apartment but didn’t want to deal with splitting my HHG between storage and shipment, so I rented the basics for bedroom and living room from Cort Furniture rental. Always ask for military discount! Or, rent a furnished apartment.
The places you mentioned are good places to buy decent items at affordable prices.
The NEX and AAFES exchange websites off DIY assembly furniture shipped in boxes - desk sets, beds, dressers, end tables, etc. So do Wayfair, Amazon, etc. For my first real guest room, I ordered a Sauder headboard, end tables and dresser and assembled it all over a weekend. Inexpensive. It was cheap, but new and clean. I went to Michael’s and bought a lamp kit with a glass jar base you could fill with sand, river stones, glass beads, shells, etc., and made 2 nice lamps. The NEX and AAFES offer both name brand and house brand towels, bedding, etc. In store and online. Free shipping. No tax. I just ordered online my replacement Zojirushi rice cooker after my 20 year old one died. Cheaper than Walmart or Target.
Take up a collection of kitchen stuff from family members and neighbors - great way to get someone’s extra glass measuring cup, excess set of mixing bowls, old but serviceable cookie sheets, battered but usable pasta pot, Tupperware, etc.