Why count
Content isn't 'brand' in a vacuum. It's a channel with a unit cost and unit revenue. If you don't count them, you're managing the channel by feel.
Unit cost
Sum it all up: team time, freelancers, production, tools, distribution. Divide by the number of content units per month. You get the honest cost of one post, email or episode.
Unit revenue
Connect content to leads and deals via UTMs, promo codes and 'where did you hear about us'. Not perfect, but enough to assess the order of magnitude.
What to do with the number
If unit revenue > unit cost by 3x — scale. Between 1x and 3x — optimize format and distribution. Below 1x — kill it or change the format. No emotions.