If it takes 7 years to start leaking and it has already been there it
may only last 6 months. If you don't know how old the black pipe is, I
would not wait to replace it
If it springs a big leak, will the water damage walls, carpets,
furniture, floors, electric panesl, etc? Then don't wait. The threads
are the thinnest part of the pipe, if it fails there the pipe could
come apart and the leak will be VERY big. Could cause expensive
Don't wait any longer than you have to.