It might be a sign of old age but I am of the opinion that if it runs fine, leave it alone.
In developing an engine millions are spent, by people who know a whole lot more than this backyard mechanic, on creating an engine that has the right balance between performance, reliability & longevity.
If you want to go racing, start tinkering with performance at the expense of reliability & longevity. If you want it to last year after year give it the best treatment in frequent oil changes using the best filters & keep up with regular preventative maintenance.
