Neither option is the safe default. Off-the-shelf software isn't automatically cheaper once you count the workarounds it forces on you, and custom software isn't automatically better just because it fits — it costs real money and time to build and keep working. The honest answer is that the right call depends on a small number of concrete factors, not on which option sounds more modern.
Fit to your actual workflow
Off-the-shelf software is built for the average case across its whole customer base. If your workflow is close to that average — most invoicing, most CRM use, most project tracking is — you'll spend less time and money using something that already exists than rebuilding it. If your workflow has a genuinely unusual step in the middle of it, off-the-shelf tools tend to force you to either change how you work to fit the tool, or bolt on a manual workaround that becomes its own maintenance burden.
Integration with what you already run
A tool that needs to talk to three other systems you already depend on is a different proposition than a standalone tool. Off-the-shelf products vary wildly in how well they integrate — some have solid APIs, some don't expose the data you need at all. Custom software can be built to talk to exactly what you already have, but that integration work is itself part of the cost, not a free side effect of "it's custom."
Maintenance and who owns it
With off-the-shelf software, the vendor maintains it, patches it, and decides the roadmap — you get updates you didn't ask for and sometimes lose features you relied on. With custom software, you (or whoever built it) own the maintenance burden directly, but nobody else can deprecate a feature out from under you. Neither is free of ongoing cost; the question is who's holding it.
Time to value
Off-the-shelf software wins here almost every time — you can usually be running on it within days. Custom software requires a real engineering timeline: discovery, build, testing, rollout. If the business need is urgent and the fit is reasonable, that speed difference often settles the decision on its own.
Scalability and control
Off-the-shelf tools scale in the ways the vendor designed them to scale, and not necessarily in the way your business grows. Custom software can be built to scale exactly along the dimension that matters to you — but only if that was actually designed in, which is a real engineering decision, not an automatic property of building something yourself.
A practical way to decide
Start with off-the-shelf unless you already know it won't fit. If you're forced into workarounds that are costing real time every week, if integration is the actual blocker, or if the workflow itself is what makes your business different from competitors using the same generic tools — that's when a custom build is worth the slower start and the ongoing ownership. We'd rather tell a prospective client "you don't need us for this, buy the tool" than build something a €30/month subscription already does well.