Pretty much every vehicle I have ever owned lists two change intervals, usually in the form of:
(my emphasis)
My last two vehicles have been Honda's, which incorporates a "Maintenance Minder" system, that is supposed to monitor the vehicle use, and display a 2 character maintenance code telling you what needs to be done.
Even with the newer Maintenance Minder system, all of the Owners Manuals include the "xxx miles or 12 months" statement in the section explaining what the Maintenance Minder codes mean.
I am also of the opinion that if you change the oil, you also change the oil filter, even when the manufacturer says you can change the oil filter every other oil change.
At the bottom of Page 119 of my Spyder's Operators Guide is the start of the Maintenance Schedule section. And it says:
So even CAN-AM recommends a mileage vs months, whichever comes first, schedule