I used to go through heads like crazy until I figured out the sweet spot. Now I replace every three to four months, depending on how they look - if the bristles are splayed out or discolored, it's time. Brushing twice a day like you do, that's about right, but yeah, easing up on the pressure changed everything for me, they lasted way longer after that and my teeth felt cleaner too without all the aggressive scrubbing.
I also make sure to rinse thoroughly after each use and let it air dry, which prevents any gunk from building up. It's all about balance, keeping hygiene up without burning through replacements unnecessarily.
