This is a good question. The answer is, whatever you are willing to do. With practice you can change tires without using any tools other than your fingers (find youtube videos to show you how.) Not using tools will mean you don't accidentally damage anything when you perform swaps, and so you can swap indefinitely or as long as your fingers hold out. Tubes might be better for this than using a tubeless setup, because every time you change tubeless tires you should add sealant, which adds up after a while. Be sure the tubes you're using match the tires you're using.