Generally the step between X.y.z releases is major enough to require upgrades of add-ons and quite a bit of other items.
The step(s) between the X.Y.z releases can sometimes break a few add-ons, adds some features, but rarely bring any major new shifts to the format of the site.
You won't be seeing a 3.x until at the least the middle of next year. With the "burn" they are getting on their slow (over 2 years) progress on a x.Y.z release, I can see them getting 2.x out before the end of the year... and 3.x MAYBE by this time next year.
If you aren't using any add-ons that require upgrade to more recent versions, then you can sit pretty steady... classic case was Bob's add-ons.. he now has a minimum XF requirement... if you use an older version, unless you upgrade you would be stuck on what you have and not get the new features/benefits of the newer versions.