Oh, and when I'm sending rather small parcels I've noticed the PO has trouble sticking the label on. So I've made a little guide out of some sheet acetate I had spare, with a rectangle cut out, the size of the PO label. Before writing the address I mark the parcel where the label will go, so I keep that area clear.
That is an excellent idea!
Did I mention I'm a control freak?
No. Really?