I have what I consider to be an excellent clientele, very loyal, and always pleased to see me.
My work has been canvassed by others more times than I can remember, but in 14 years have only lost work for the following reasons:
a) customers moving house;
b) customers dying;
c) my own reliability when I took on too much and couldn't keep up with the workload;
d) poor quality (1 known instance in 14 years!;
e) 1 instance of undercutting, which I was undercharging anyway!
So my personal experience is, that in the main, customers are very loyal, if you build a good reputation for quality and reliability, coupled to being reasonably priced and having the kind of personality which makes them comfortable in your presence. I have also learned to deal with any reliability and quality issues promptly, so that any possible damage to reputation is limited and repaired with consciencious effort and vigilance.
Realistically, it is never going to be a 100% racing certainty that people will remain loyal, as there may be changes of circumstances which force the customer to dispense with our services, which are beyond their control. But I believe if we do a high quality job, for a fair price, are honest, friendly and reliable, our customers will be as loyal as their circumstances allow them to be.
John