Off-the-shelf is the right default

If a subscription tool does the job, use it. It is faster to start, cheaper up front, and someone else maintains it. For email, accounting, scheduling and most common needs, building your own would be a waste of money and time. Start by assuming you should buy, not build.

The test: is this how you compete?

Custom software earns its cost in one situation: when the process is core to how you win, and no tool fits the way you actually work. If your edge is a workflow your competitors cannot copy from a shop shelf, bending your business to fit a generic tool quietly erodes that edge. That is when building pays off.

The opposite is just as true. Building custom software for a process that any standard tool handles is paying premium for a problem you do not have.

Count the real cost of the workaround

Many businesses already run on a hidden custom system: a tangle of spreadsheets, manual copying and one person who knows how it all fits together. That workaround has a cost in hours, errors and key-person risk. When that cost climbs past the price of a proper build, the spreadsheet is no longer the cheap option, it just looks like it.

You can do both

The smartest setups are rarely all-custom or all-bought. Keep the off-the-shelf tools for commodity tasks, build custom only for the workflow that is genuinely yours, and connect the two so data flows between them. You spend money where it creates an edge and save it everywhere else.