> There is no telling if it will actually save time. You could be messing with configurations, have to learn their docs, etc... Or future migration could be expensive in both time and money.
Sure. Every situation is different. This isn't meant to be universal. There absolutely are cases where rolling your own may be more efficient. However, my argument wasn't that existing solutions are no effort, just that they are often less effort than trying to do something completely custom or self managed.
Regarding future migrations, the same can be said in the opposite direction as well. You may get to a point where you need to migrate away from your custom solution to something more standard and you'll face similar time/money issues.
> Custom is more configurable.
Sometimes this is the case and sometimes it's not. Sometimes custom is very narrowly focused and as new use cases emerge requires significant rework.
> People overestimate their time worth? Sure you can theoretically work for 75$/hr, but can you get overtime/additional revenue that easily?
The number will vary for everyone. $75 may be too high for some and too low for others. If you're an attorney sacrificing billable time to do something administrative that could be outsourced, $75 may be low. The idea is to tie an actual realistic number to the value of your time.
> What is your value add? If it's software, I might suggest custom is best because that's your business. If you mash a bunch of software suppliers together, you become a middle man. I'm not saying that doesn't work, but I've seen companies go back and forth on this.
In software, I think it's important to know what your product is and to focus on your core competencies. I've seen lots of engineers decide that they need to build something from scratch that doesn't directly relate to their product. Could you build your own credit card processing system? Sure, but unless your business is credit card processing, it probably makes more sense to use something like Stripe. The same goes for lots of different aspects of your product and business.
I'm simply suggesting that you have a limited amount of time in each day and you should do what you can to get the most value out of that time. Don't ignore the value of your time and sacrifice it needlessly.