Im going to stick my neck out here, and wait for the retaliation. I believe because you are in a personal service industry, alot of this is built up through trust and familiarity, remember your encroaching on their personal territory. Not knowing names, builds a bridge of unfamiliarity, personally I think it is essential to build good customer relations with people to sustain longevity and loyalty
If you become impersonal I think you will be treated as come and go (this is where the phrase, "ive had the same cleaner for years") thats built out of trust.
Dont know thats just the way, I know if somebody was at my house, I would want to know their first name and be on that level with them.
Community comes into it also, I think. Because you are a community business, the saying word of mouth works both ways, you also get a bad reputation if you do a bad job.
So I think its good to be on some sort of semi-familiar basis, because I think that builds loyalty and retention
Not over friendly, but professionalism with I know your name, I know your personality, I know how to react to you