The newsfeed placements (desktop and mobile) are tricky. It’s “personal” space for Facebook users, so you wouldn’t want to burn out from a high frequency or push overtly promotional messaging. Save that for the dark posts to fans and the RHS placements.
Above we have a newsfeed that that is at a frequency of 6.5. The CTR has fallen to 0.352%. We like to see CTR stay above 1% and frequency below 2.0.
You can also look at your negative feedback to tell if users are weary. Grab this via your page insights, downloading the clunky CSV file on post insights. You can also expand the comments to see if you have people demanding that you “get off my Facebook”.
Besides user experience, a poor CTR or quality score (now defunct) is financial, Facebook will charge you more. 126 clicks for $91.40 is 72 cents a click. Had this ad not burned out, we’d likely see a 1% CTR (3 times better) and 24 cents a click (a third the price).
The exception to a seemingly high frequency ad is the page post ad that is always on “promote most recent post”. Provided that you’re posting daily, this ad is not going to burn out, no matter the budget you allocate against it. The true frequency is lower than stated.
Facebook is progressively limiting the frequencies of newsfeed ads based on your negative feedback. The rule doesn’t apply to RHS (right hand side) placements, since users expect ads there.