Are budget mechanical keyboards durable enough for daily use?

Yes. Mechanical switches are rated for 50 100 million keystrokes, which far exceeds most membrane keyboards. The switches themselves will outlast the keycaps and case. Build quality varies more than switch quality at this price range look for aluminum or reinforced plastic cases, PBT keycaps (they resist shine), and detachable cables (the most common point of failure on wired boards).