I don’t know about saving money, but around here airlines have been creeping up checked bag fees for years. You used to get one free checked bag but when they started charging for all checked bags people started trying to fit thier entire vacation worth of stuff into carry-on. The bags I see people trying to fit into the overhead now are huge and just barely fit in the compartment on smaller planes. The airlines know what’s up though since they’ll charge for checked bags but then announce repeatedly before the flight that they’re looking for volunteers to check their carry-on to its final destination for free. I actually saw one airline enforce the carry-on sizing device as people were boarding and forced any oversize bags to be checked. A lot of unhappy people that day.

But if you microwave fresh water in a clean cup you’re missing the flavor from the scale and other build-up in an infrequently cleaned kettle.