Best ways to associate multiple programs/campaigns with one landing page
I have some "evergreen" landing pages in production (email sign-up, request a demo, etc.) that tend to be secondary CTAs on a lot of collateral, so I'm constantly driving traffic there. Currently, I've been duplicating these landing pages for individual campaigns so I can add respondents and program status to the right things (e.g. if they request a demo from a given email campaign, they're marked successful in that email campaign, whereas if they're organic traffic to the demo form, they're added to the organic program).
Having multiple copies of the same LP is, for obvious reasons, a drag.
I've put some consideration into just using campaign URL parameters or something in order to identify traffic sources, but I'm not sure if that's a good plan. Is there a reason to/not-to just have smart campaigns of "filled out form XXX" with criteria of landing page URL contains "utm_campaign=october-email" or whatever?