Visible moisture
If you notice water under a sink or near a connection, take a photo. Explain whether the area stays wet or whether it seems tied to use of a fixture.
A problem that comes and goes may not show up during your walkthrough. Bring the earlier repair notes so we know what has been reported. For example, a toilet that occasionally keeps filling is worth mentioning even if it seems fine when you visit.
Tell us when the next tenant is due to move in. You can then discuss the items you want checked and our availability to complete the work.
Send any plumbing notes from the previous tenancy so we have the background.