Hi Dave,
Sorry but I have to disagree with you. Getting a tip has no reflection whatsoever on your pricing.
A tip is based on your loyalty, regular service in all weathers and months of the year. Your services you have provided and the fact that your customer appreciates you and what you have done for them over the last 12 months. It is also the season of goodwill and it is generally an accepted practice to tip all people such as bin men, postman, milkman etc.............
Now, if you had a customer that you charged £8.50 each month and everytime they paid you, they gave you £10 and said keep the change, then you would have to question your pricing!
A once a year tip is completelty different??