[logn]

I was referring to just normal, non-automated emails above. An alternative to say, Google Apps, where I can fit an entire email server on a VPS with less than 400 MB memory, vs $10/user with Google.

I agree with you for transactional email.

For any DIY project there's a limit where you really should just pay someone. But for instance I run wrote my own Stripe-based invoice generation, subscription management, and dunning vs paying for a service. It works for me for now. If one day my little app breaks down if/when I have thousands of customers then I'll outsource it.

I run my own private Git repo vs paying $7 to github. Etc.

Edit: to add, I am selling software I wrote basically from scratch (and there's no way around that). Like a comment way up above, my biggest risk is in that stack. I suppose with the uber-paranoid mindset I should have outsourced my own development work. At the end of the day, someone like me is responsible for something important. It's not life or death with my software so at least I got that.