I text all my customers the night before and I don't really have a problem.
I get the odd customer on holiday or having work done, but that would be the same whether I text or not.
And I certainly can't be bothered to climb gates. I don't even do any awkward access or anything that needs a backpack!
I get the odd one ask 'what time' but that's usually because they want to be in, to pay me, or have a quick chat. Sometimes I may offer AM or PM.
Yes, you do get messers, but I think texting is a good way of weeding them out.
I only want customers who WANT their windows cleaned regularly and that's pretty much what I've now got.
Also, customers use texting as the preferred method to contact me about FSG, conny, patio, wall cleans etc, so it sort of works both ways.