Excel, SaaS or custom software: when building your own tool pays off

Almost every company goes through the same three phases: first a spreadsheet, then a subscription to a product that does almost what they need, and sometimes a tool of their own. The question is not which one is best, it is which phase you are in.

The three options, without romance

The spreadsheet is the most underrated tool there is. It is effectively free, everyone understands it and it adapts to anything in five minutes. It carries far more weight than software vendors like to admit.

SaaS (a subscription product: a CRM, a point of sale, a project tracker) gives you in an afternoon what would take months to build. It is maintained, updated and tested by thousands of companies. In exchange, your process adapts to the product, not the other way round.

Custom software does exactly what your business needs, no more and no less. It costs more up front and does not maintain itself. Its real advantage is not being "more complete": it is fitting.

Signs you have outgrown the spreadsheet

It is not about file size, it is about friction. Watch for these six:

1. Several versions of the same file exist and somebody has to merge them by hand.
2. Only one person knows how it works. When that person is on holiday, the process stops.
3. Data is copied between systems. Someone moves orders from email into the sheet every morning, and from the sheet into the invoicing tool.
4. Errors surface late. A formula stopped filling down correctly three weeks ago.
5. You cannot check it from your phone while you are in the warehouse, on site or on the boat.
6. You need two people working at once on the same thing and you cannot.

One or two signs: stay in the spreadsheet and tidy it up. Four or more: you are paying the cost in hours without seeing it on any invoice.

When SaaS is the right answer

Almost always, if your process is standard. Invoicing, bookkeeping, running an online shop, tracking hours or signing documents are problems millions of companies have identically. Building your own invoicing product is throwing money away.

SaaS also wins when you need to start tomorrow, when the process is still changing, or when the volume does not justify an investment.

Where it falls down: when you pay per user and the team grows; when the 20 % it does not cover is precisely what makes you different; when your data is locked in and exporting means a thin CSV; and when you end up running three subscriptions that do not talk to each other while somebody bridges them by hand.

When building your own pays off

Four criteria. Meet two and it is worth studying; meet three and it almost certainly adds up.

• Your process is your advantage. If you do something differently from your competitors and that is why people buy from you, forcing it into a generic product flattens it.
• Subscription costs are high and rising. Add up what you pay per year in tools and multiply by five years. That figure is the real budget to compare against.
• There is repetitive, measurable manual work. Two hours a day of copying and pasting is around 500 hours a year. That number justifies plenty of projects.
• You need to connect systems that do not talk. Where SaaS falls short is almost always the join between pieces.

Costs, by range

Option	Indicative cost	What you get
Spreadsheet	Near zero	Total flexibility, no maintenance, no error control
SaaS	€20 to €200/month, often per user	Ready tomorrow, maintained, on the vendor's process
Scoped custom tool	From €6,000	One concrete process solved: job sheets, records, internal bookings
Custom management system	€15,000 to €40,000	Several processes, roles and permissions, reports, integrations

Always add maintenance: 10 to 20 % of the development cost per year. Custom software without maintenance ages exactly like a website.

Examples from local businesses

Without inventing clients, these are common profiles around Girona where the balance tips:

• A workshop or an installation company with paper job sheets. Digitising the sheet with a signature on the phone and pushing it into invoicing is a scoped project with a clear return.
• A bakery or a food producer with batch traceability. Audit requirements are highly specific; generic products rarely fit without being bent out of shape.
• A campsite or a hotel with a PMS that covers 80 %. The remaining 20 % (maintenance, incidents, seasonal staff) ends up in WhatsApp and notebooks.
• A distribution business taking orders by email, WhatsApp and phone, then re-entering them by hand into the ERP.

In all four the pattern is the same: SaaS handles the core and the manual work concentrates at the edges.

Frequently asked questions

Can I combine SaaS and custom software?

That is the most common setup and usually the most sensible. Keep SaaS for the standard parts (accounting, payroll) and build only the piece that differentiates you, connected over an API.

How long does custom development take?

A scoped tool, 6 to 12 weeks. A management system, 4 to 9 months depending on scope. Be wary of anyone promising far less without having seen your process.

Will the code be mine?

It should be, and it should say so in the contract. If the supplier keeps ownership, you have swapped one subscription for another with fewer guarantees.

What if my process changes in two years?

Well-built custom software gets modified; that is precisely the argument for it. What to avoid is coding a process you are still inventing: stabilise first, automate after.

Conclusion

Stay in the spreadsheet while it works, use SaaS for anything standard, and build only what sets you apart. If you are unsure which phase you are in, see how we approach custom software development or describe your process and we will tell you whether building is worth it.