The amount of use is certainly a factor - Omega clearly states this in their service recommendations:
As they say, it depends on the conditions in which it was worn, and that would include how much it is worn. Wearing the watch less can extend the service intervals, but it's not a 1 to 1 relationship. So if for example a service is needed after 5 years of constant wear, wearing it 1/3 of the time won't mean it can go 15 years.
The reason is that modern oils will dry up over time. How long they last depends on the specifics of each oil, the amount that is applied, etc. When they do dry up, it looks like this:
The older natural oils that used to be used in watches failed in a particular way - they became more viscous as time went by, and the result of that is that the oil gummed up the watch and would cause more severe performance issues. So within say 3 years or so, you would see the power reserve drop, timekeeping would suffer, etc. and eventually it would just stop. This prevented a ton of wear from happening.
Modern oils don't fail this way - they dry up like you see above, and they don't gum the watch up. The watch continues to run, but is running dry basically. I've had watches come in that based on just how they run on the wrist, you would think they were just serviced, but were completely dry inside.
If you have a watch you care about preserving the parts inside, then I personally wouldn't stretch the service interval past maybe 8 years or so.
Cheers, Al