My next door neighbor works for our cable company installing and repairing fiber optic lines. The other night after work he was telling me about having to repair a very expensive line not once, but twice because a tree company was attempting to plant some trees and never called to confirm line location.
At work we make a call to 811, Call Before You Dig (CBYD) at almost once a day for client properties and I have called at my own house for more than one landscape project. The service is free and with a little planning early in your week, they will mark your yard in time for your weekend project. This simple step will save you personal harm and inconvenience.
Even if you are not doing the work yourself, make sure the company you have hired has your yard marked before digging. It will save you the trouble of getting important lines fixed.