Off-the-shelf software is usually the right first answer. It is quicker to adopt, someone else maintains it and it reflects how many businesses work. The question is what to do when it stops fitting.
Custom software starts to make sense when your process is a genuine advantage and the tools force you to work around it; when staff copy data between several apps every day; or when the reporting you need depends on joining systems that do not talk to each other.
It makes less sense for needs every business shares, such as email or payroll, where mature products already exist.
Before deciding, map the workflow as it happens today, count the manual steps and note who owns each one. That map is useful either way, and it is where a good custom build begins.