1) tl;dr your CAC (almost) always goes up over time. So, if it's not good or barely good in the beginning, you'll want to think through some things.
And there are exceptions too...read on >>
When you think about, CAC is "lowest" in the beginning, because you have no customers. You can get the low-hanging fruit cost effectively.
Think ad spend. Outbound sales spend. etc. First movers are ready to buy quickly.
E.g. sometimes ad prices go down or up depending on what your competitors are doing, etc. Like now is a great time to buy FB ads even though it has nothing to do w/ your company.
But that's a local minimum.
That's when CAC goes up. If your immediate payback goes up to 3 mo payback, that can be ok - you now know your LTV better.
SEO, for example, is the opposite.
BUT, your tradeoff here is this doesn't happen immediately.
So even if you start a repeatable SEO process on day 1, you have to last 3 yrs w/ basically no $$.
It CAN be done. and you CAN build a big business from SEO (@NerdWallet is a great example), but it's important to know what you are walking into.
You still have to think of SEO in a process-oriented way like other types of mkting.
a) how much does it cost you to get a link? (on what type of domain / site)
b) how much does it cost you to write an article (what cat? what type? on what site?)
Compute this based on the cost of your ppl you contract.
a) how much traffic did link / article get you? conversions? how much was it worth? after 1 yr? 2 yrs? etc
b) can you rinse & repeat the process to build links / articles -> traffic -> conversions produced?
And earn more rev than those costs?
And then track ROI over time to know how to improve your SEO process / spend.
That upfront cost for SEO is still a challenge to deal w/.
a) aim for immediate payback
b) most cust acq channels (ads / sales) go UP over time, so you'll need to retain well & upsell later as payback period goes up
c) SEO - need to build a repeatable process & be cheap