Most small business owners don’t get into trouble because they’re reckless. They get into trouble because daily life and business life share the same receipts. The phone that’s “mostly for work.” The car that also brings the kids to sport. It feels harmless, until your VAT return (BTW-aangifte) and your year-end figures quietly start telling a story the tax office doesn’t accept. And then it’s not theory anymore: it’s repayments, corrections, extra admin, and a dent in trust.

The key idea is simple: if an expense is partly personal, only the business part counts as a business cost. That personal portion is what we call the private share (in Dutch you’ll hear privé-aandeel or privégebruik). It matters for income tax, because you shouldn’t lower your profit with private costs. It also matters for VAT (BTW), because VAT is only reclaimable for business use. If you reclaim VAT on something you partly use privately, you’ll need to correct that private part, meaning that VAT is not deductible on that portion.

Here’s a concrete example I see all the time. You buy a phone with a €60 monthly subscription, and you estimate you use it 70% for business and 30% privately. The business logic is straightforward: only 70% of the cost belongs in your business figures. The other 30% is private, even if the invoice is in the company name and the payment comes from the business account. The VAT side is where people slip: you can only reclaim VAT on the business portion. On that private 30%, the VAT is effectively yours to carry. If you reclaim everything and “sort it out later,” later tends to arrive as a correction, often at the least convenient moment for cash flow.

The practical risk isn’t that the rules are complicated; it’s that the mix is invisible unless you make it visible. If you don’t record a reasonable split, your accounts become optimistic by default. That shows up as a profit that looks lower than it should, VAT reclaimed that you didn’t fully earn, and an admin trail that’s hard to defend if someone asks, “How did you decide this?” A small correction can become a larger one when it repeats across months, and suddenly your tidy quarterly routine turns into a stack of backtracking.

You don’t need perfection, but you do need consistency. Pick a method that matches reality, an estimate backed by something simple, like a usage overview, a mileage log, or a fixed percentage you can explain without squirming. Separate what you can: a dedicated business phone plan is boring, but boring is good in bookkeeping. And when the split is unavoidable, treat the private share as a normal fact of business life, not a failure, just make sure it’s booked as private, and make sure the VAT on that private portion isn’t quietly claimed.

I like calm accounting because it protects calm entrepreneurship. The private share is not a moral issue; it’s a clarity issue. If you tighten this now, one or two recurring costs, one sensible split, one habit of checking your VAT claim against real use, you reduce risk without adding drama. The goal isn’t to run a “perfect” administration. The goal is to run one that holds up when you’re busy, tired, or audited and still lets you sleep well while the invoices go out and the cash comes in.