I have a policy of doing one little extra thing for each customer
Every now and then i do one of these things below.
1. wipe the outside of the gutter on a conservatory
2. wash a garage door,
3, wash the electric and gas boxes outside.
4. wash an outside old coal hole door.
I think this way my customers appreciate that i do a good job , and do above and beyond the service they pay for,
i dont lose any customers at all.,
I let them know too , telling them i could not resist cleaning it , they like that
Do one extra thing free for all your customers. even just the once.