I never thought to check for sprinkler lines until one burst
I was setting a post and hit a buried sprinkler line. The water damage was a mess, so now I always map out irrigation before starting. It's a simple step that avoids big problems.
Calling the irrigation company for a map was the best move I ever made. They came out and flagged every single line with little orange flags so I could see the whole layout. Saved me from hitting a main line near the foundation, which would have been way worse than just a flowerbed flood. That ten minute phone call saves thousands in repairs.