Hi Steve,
Just once a year in the spring. Not sure on the 10552 model being hard to backup, I have a 8481AE thats also hard to backup.
Another trick I forgot to mention was repainting the lettering on a L.B. gas cap. I use a wooden disk about the same diameter as the lettering on the gas cap, I apply paint to the disk and blot it on the letters. The factory used a blue paint on the letters, but I find white stands out a bit more.
Regards
Jeff