Write a listicle of common mistakes in a specific niche

You write for a blog aimed at agencies offering WordPress maintenance retainers.
You want a post on common pricing mistakes, based on patterns you've actually seen
across dozens of agency consulting calls, not a generic "avoid these pitfalls"
filler list.

REAL MISTAKES OBSERVED: [
"pricing retainers based on hours estimated rather than the value of uptime/security
to the client",
"offering unlimited revisions on a fixed retainer price",
"not defining what counts as 'maintenance' vs a billable project, leading to scope
creep",
"undercharging new clients to win the deal, then eating the cost for the life of the
contract",
"no clear off-ramp clause, so a bad-fit client can't be exited cleanly"]
AUDIENCE: [agency owners currently running maintenance retainers, or about to start]

Work through this before drafting:
1. Order the mistakes by how much they actually cost the agency over time
   (undercharging for the life of a contract and unlimited revisions both compound
   every month), not alphabetically or randomly, the reader should see the most
   expensive mistake first.
2. For each mistake, explain the reasonable-sounding logic that leads agencies into
   it in the first place ("unlimited revisions" sounds generous and client-friendly
   when you're trying to win the deal), before explaining why it backfires, since
   naming only the mistake without the reasoning behind it makes the post feel like
   it's talking down to the reader.
3. Edge case: "unlimited revisions" isn't a universal mistake, it can work fine for a
   small number of high-value, low-ticket-volume retainer clients where the agency
   has slack capacity. Don't present it as an absolute rule, name the specific
   condition under which it's actually a reasonable choice, alongside the more
   common situation where it isn't.
4. Give each entry a concrete fix, not just a warning. "Define maintenance scope"
   needs an actual example of what that boundary looks like in a contract, not just
   "be clear about scope."
5. Resist padding to a round number. If there are genuinely 5 real mistakes worth
   covering here, publish 5, don't stretch to 10 with filler entries that dilute the
   ones that actually matter.

Draft the full post: intro on why these mistakes are so common (they mostly come
from reasonable instincts, not carelessness), then each mistake in the ordered
structure above (mistake, why it happens, the cost, the fix, and the exception where
relevant).

Replace the bracketed mistakes and audience above with your own.