Here's something to ponder.
Last year, my car's MOT had an advisory: rear brake pads worn, replace soon.
I didn't change them because just one month earlier the Mercedes garage told me the pads were 40% worn, so in good condition.
My car was in the Mercedes garage again about three weeks ago, and again they told me the pads were in good condition.
The car was MOT'd again yesterday - with the same brake pads as last year.
And guess what?
It passed with no advisories... despite having the same pads as last year.
It's amazing how the pads have actually got less worn with a year's worth of use.

Last year: