For me, base camping occurs when a group (1 or more) arrives at a camp site and stays for 3 or more days. In and out weekend trips do not qualify. Usually a plan is set in motion to travel to a site or area to set up camp intending to stay there for a while. Of course, events can alter plans and an unscheduled longer stay becomes a part of your trip. By my definition, 2 or more base camps can be used on one trip. Resupply of food can be a part of your plan. A base camp trip could be as simple as getting to the island in Fall Lake and staying there. That is a flat camp within view of the take out. I am already hoping to do that when I am in my 90's whether I paddle or take a tow there. On the other end, travel hard and far into the Quetico or BWCA center taking as much time to get there as you want.
"Such sights as this are reserved for those who will suffer to behold them." -Eric Sevareid
I agree, 3 days makes one a base camper, I am quick to admit I am one. Our first big trip in 2017, we kayaked Big Fork River from Big Falls to Loman in 4 days. The idea of not having a set campsite, pushing to get to camp only to be pinned down by current was exciting, but you woke up smoked, ate chow and then packed up and moved out. Took its toll on us and we are pretty young and fit. Granted, we caught a 53" sturgeon from a kayak, tons of small mouth and hooked into some muskie and let them tow us around a bit, which was fun. Also we had some good camraderie and the "suck" is always something that makes a great memory that you can laugh about later.
We went to BWCA in 2018, basecamped 5 nights, had a blast. We put in a ton of miles paddling around, but having a set camp with fresh water and dry wood waiting was refreshing. The portages killed is though, our kayaks weigh 113 and 95 lbs.... Then there is our gear (which is minimal). Portages are short and easy, but we carried our yaks and beat ourselves up.
2019 brings 10 days in Quetico, we likely will jump once, maybe twice, but will stay at that 3 day + mark for occupation. Bonus to Quetico.... Only portage if you feel like it...