Big win turned into a $1200 loss on a simple deck repair job

Man, up here in north jersey the weather's been brutal this spring, and I took on what I thought was an easy deck repair for this old ranch house in Montclair. Quoted the guy $800 flat rate using Trex composite boards since he wanted something low-maintenance that wouldn't warp like the old pressure-treated stuff. Everything was going smooth until I hit a hidden rot pocket under the joists, turned into a full tear-out and rebuild, now I'm out $1200 in materials and time with no extra pay. Feel like such a chump for not probing deeper upfront, but damn, these 50-year-old decks are full of surprises. Anyone else had a 'quick fix' turn into a money pit like this? Saw a similar rant on r/handyman last week about backyard projects gone wrong. And that guy in Handyman Nation FB group was talking about always adding a contingency clause, wish I'd listened.

Ugh, decks are the worst for hidden crap like that, lost a whole afternoon on one last summer.

Same here, thought it was just loose boards and ended up replacing half the frame, customer acted like it was my fault.

Screw these homeowners who lowball on inspections, we all know better but still get burned.