I experience a low or spongy brake pedal about once every two weeks

if air in the lines is the only cause, it'd take me about an hour to bleed all the brake system. That's about $100 plus the brake fluid in most areas. I'll give you an estimator link and shop directory. You should flush the brake system and clutch if you have one about every two years, say I. https://repairpal.com/estimator/mazda/tribute https://repairpal.com/mazda-repair-in-cleveland-ohio