Forget the binary between long duration and low season for travel; it's a matter of smart timing.
Focusing on a fixed duration like two weeks ignores the flexibility that is the real key to the economy.
In Japan, for example, taking three days midweek outside school holidays can be much more affordable than two weeks during Obon or Golden Week.
It's not the length of the stay that matters, but the ability to navigate off-peak demand for advantageous rates.
The real strategy is to study local holiday and school calendars, not to stick to an arbitrary duration.