Waiting for fertile CM or app's predictions?

Do you guys wait to BD until you see fertile CM? Or do you try to time it around the days that the app says your most fertile even if you don't have any EWCM?
I'm just wondering in case I don't start seeing signs of fertile CM before my first predicted fertile day, if I should time it based off the CM or go ahead and time it based on what the app is telling me (first predicted fertile day is in 2 days and my CM is basically non-existent at the moment). 
And is it safe to say you're not getting ready to ovulate if you don't see any fertile CM?
(Starting 2nd cycle after getting off the pill. I ovulated last month but didn't get a BFP. A little worried my cycle may not be predictable even though I ovulated the first cycle coming off the pill.)
Thanks for any help ladies! :)