An old quote I always liked:
First time founder focuses on product (building)
Second time founder focuses on distribution (marketing)
Third time founder focuses on culture (delegating)

Ultimately I think it depends on what kind of thing you’re creating. Some businesses need more building, others need more marketing. The more complete your product (does everything customers need), the more you’re just doing marketing.

I don't think there's a perfect split, as it depends on a ton of things: what the app is, is it mvp, what's your market and can marketing be automated, etc.

For me, some weeks/months tilt most to building, while others tilt to marketing. In any case, once a product reaches some kind of PMF, I try and do 80/20 on marketing/building.

As others have said, it ebbs and flows. I built some basic features, then tried to market to people for a while, got a few customers, they asked for things, now I'm back to building until the "must haves" are done (will be later this week).

Then I'll go back to marketing until I have more customers, and so on.

Surviving 😂 and having a cofounder that loves that part. In my case, I handle the first part, but not so much the second.

As an indie founder/developer, my rule of thumb is if I don't have (enough) customers, I am not spending enough time marketing.

I tried one day of building, then one day of marketing, etc etc.

Those didn't work for me. :(

What works for me now is doing 50/50 split. Check out codingweekmarketingweek.com to guide your path throughout the week.