You should always think about how much it'll cost for you to roll out and maintain something vs how much it would cost to buy the service from a vendor.
Chances are your volumes are low enough it will be actually cheaper to run with something like New Relic or Datadog. When the monthly bill starts reaching 10% of what a dedicated person would cost, it's time to plan your move to self-hosted.
> it's time to plan your move to self-hosted.
No, it's always time to plan the move to self hosted, and just occasionally choose someone else to be the "self." Because once a proprietary vendor gets in the stack, evicting them is going to be a project
I'm aware that this doesn't split cleanly down the "saas only feature" or the evil "rug pull" axes, but I'd much rather say "I legitimately tried to allow us to eject from the walled garden and the world changed" versus "whaddya mean non-Datadog?"