Many heads have indicator bristles that fade around the 3-month mark - use that as your cue but swap sooner if the tips splay or feel scratchy. Frayed ends don’t clean worse; they can start to irritate gums and wear enamel. I also replace a head early after a cold, flu, or strep to avoid reintroducing germs.
I’d focus on a true one-hand one-step fold that self-stands and weighs under 15 lb; in your budget, the Summer 3Dlite and Kolcraft Cloud Plus are reliable, and the GB Pockit folds tiny for planes but rides rough and has a small canopy. Prioritize a 5-point harness, a latch that locks the frame closed, and front wheels that can lock straight for uneven surfaces. Quick tip: measure your trunk opening and practice the fold in-store with one hand while holding a bag, then gate-check it in a cover so it doesn’t pop open.
