Retention or acquisition: where the first marketing dollar should go

A new app has a small budget and a big question: ads, or more product? The instinct is ads, because ads produce a number that goes up. The better answer comes from a different number.
The number to check first
Of the people who installed two weeks ago, how many used the app this week? Call it week-two retention. It is the simplest honest measure of whether the app has found a place in anyone's life. If it is low, every install you buy is a person who will leave, and the budget mostly funds the leaving.
The rule
If week-two retention is weak, the first budget goes to the product: the first session, the first result, the reason to come back. If it is healthy, the first budget goes to traffic, starting with the cleanest channel for your category. If you do not know the number, the first budget goes to finding out.
The exception: the store page
Fixing the store page is marketing spend that pays regardless of retention, because it improves the conversion of every organic visitor you already get. Subtitle, first screenshot, ratings prompt: these cost little and help even while the product is still finding its feet.
What "fix the product" means in practice
- Make the first result personal.
- Shorten everything between install and that result.
- Give the second open a reason: what they made last time, what is new today.
- Read every review and every support message from the first hundred users.
Then buy traffic, carefully
Once week-two retention is something you would be happy to show someone, start with a small, clean channel and measure trials and renewals, not installs. Retention is what you are multiplying; acquisition is the multiplier. Get the first number right before you pay for the second.