Apps, dashboards and assistants for the processes that are specific enough that no off-the-shelf product fits them properly.
When the process is specific to how you operate, and the workaround is a spreadsheet that several people maintain by hand.
The spreadsheet is the signal. It means the process is real, it is repeated, and no product you have bought covers it. That is the point where a small internal tool usually pays for itself quickly — not because the software is complex, but because the manual coordination around it is expensive.
If an off-the-shelf product does fit, we will say so.
The narrowest thing that removes the manual step — one screen, one workflow, in production within a few weeks.
Internal tools fail by being scoped as platforms. We build the specific thing that removes the specific pain, put it in front of the people doing the work, and extend it based on what they actually hit.
You, or another team. It is handed over versioned, documented and running on infrastructure you control.
An internal tool that only one outside party understands is a liability. Handover is part of the build.
Thirty minutes on a call is usually enough to tell whether this is the right shape for it.