I put a next clean date on the bill, with a locked gate & payment policy. If they forget..tough..full payment is still due and it works they only forget once. But of course...i am CRAZY for doing this and saving myself time an hassle asking people the night before effectively if its OK for me to clean their windows (giving them control)
No need to text, just turn up as detailed on the schedule. bang. I have one particular customer who always forgets, i think in the last 4 years he has only remembered to open his gate like 6 times, i just clean what i can and he pays me in full. Sometimes he remembers to open the gate, he doesn't care really as long as i come to do them when i say i will.