140mm refractor vs 155mm refractor

How much of a difference would I see in a 140mm refractor vs a 155mm refractor? Would the increase in aperature in the 155mm refractor be worth the added cost?

Debbie

It will be hard for a novice to tell the difference.
An experienced observer with the two scopes side-by-side
will notice more a little detail on moon and planets,
and maybe some fainter stars, in the larger scope.

It depends on which two refractors you are talking about.