Given the choice between spending a day or a weekend building something in house, or using a remote web service, I will always bring it in house. Because it's ridiculous to rely on some remote service if you don't have to.

If it will take me a couple of months to replicate something which already exists as a web service, I will usually use the web service. If only temporarily.

None of the web services mentioned so far on this page seem significantly difficult to replace, and suggesting that people use them seems rather ill-informed advice...

I think it matters whether your business has found product/market fit. Before product/market fit, taking the time to build things in house increases risk--risk that you're wasting your time on a product no one wants. After product/market fit, it reduces risk--risk that your product that people are paying for will have reliability problems.

>Given the choice between spending a day or a weekend building something in house

Remember that building it is not the only cost; you also have to consider the costs of maintaining it and keeping the servers running.