Training is fine, but if I were a god I wouldn't approve bigger changes by a newbie.

You have to keep in mind that there might be plenty of inter-dependence.

Status quo is that

Show nodes created within the [1] past days [submit]

is shown after "Clearing the last checked time".

My suggestion, add a radio to safe the election permanently

Show nodes created within the [1] past days [submit]  o adjust last checked

Even this minor change could potentially lead to problems elsewhere, but I doubt anything bigger would be approved.