Buying your first home is exciting — and it's also one of the easiest times in your life to make an expensive mistake. The mortgage process is complex, lenders aren't always on your side, and small errors can cost thousands of pounds or even derail your purchase entirely.
Here are the 10 most common mistakes — and exactly how to avoid each one.
Many buyers apply for a mortgage only to discover their credit score has issues — old defaults, wrong addresses, or simply a thin credit file. By then, it's too late to fix before needing the mortgage.
Check your score with Experian, Equifax, and TransUnion at least 3–6 months before applying. Fix errors, pay down credit cards, and register on the electoral roll at your address.
Your bank may offer you a mortgage — but it almost certainly won't be the best deal available. Banks only offer their own products. A whole-of-market mortgage broker has access to hundreds of deals from dozens of lenders, including exclusive rates unavailable directly.
Use a fee-free broker (they earn commission from lenders) or comparison sites before committing to any deal.
First-time buyers often budget for the deposit and the monthly payment — then get blindsided by everything else. Budget for: Stamp Duty (first-time buyers get relief), solicitor fees (£1,000–£2,500), survey (£400–£1,500), mortgage arrangement fee (£0–£2,000), removal costs, and immediate home improvements.
As a rule of thumb, budget an additional 3–5% of the property price on top of your deposit for these costs.
Lenders calculate affordability based on today's rates and their own criteria. But if you borrow the maximum at a 2-year fixed rate and rates rise when you remortgage, your payments could jump significantly. Many buyers found this out painfully when rates rose rapidly.
Borrow comfortably below your maximum, and stress-test: can you still afford payments if the rate rises 2%?
The lender's valuation is not a survey — it just confirms the property is worth what you're paying. It will not tell you about structural problems, damp, roof issues, or electrical faults. A full building survey can reveal problems that save you tens of thousands — or help you renegotiate the price.
Never skip a proper survey. A HomeBuyer Report (£400–£800) is the minimum. A Full Building Survey (£600–£1,500) is essential for older or unusual properties.
Lenders re-check your finances right before completion. If you've changed jobs, taken out a car loan, maxed a credit card, or made unusual transactions, they can withdraw the mortgage offer — even days before completion. This has happened to buyers who went car shopping after exchange of contracts.
From mortgage application to completion: no new credit, no job changes, no large unexplained purchases.
A Mortgage in Principle (MIP) — also called an Agreement in Principle — shows sellers and estate agents you're a serious, creditworthy buyer. Without one, many sellers won't accept offers, and estate agents won't prioritise showing you properties. It's free, fast, and uses a soft credit check that won't affect your score.
A mortgage with a 4.5% rate and £2,000 arrangement fee might cost more than a 4.7% rate with no fee — especially on a smaller mortgage or short term. Always calculate the total cost over the deal period (monthly payment × months + all fees) to find the true cheapest option.
When your fixed, tracker, or discount deal ends, you're automatically moved to the lender's Standard Variable Rate (SVR) — which is usually 2–3% higher. Thousands of homeowners overpay every year simply because they forget to remortgage. Set a reminder 3 months before your deal expires and start comparing new rates immediately.
If you died tomorrow, your partner or family would still owe the mortgage. Mortgage life insurance is relatively cheap (especially when you're young and healthy) and pays off the outstanding mortgage balance if you die. Critical illness cover and income protection are also worth considering. Don't start a mortgage without at least basic life cover in place.
Summary: Your Mistake-Prevention Checklist
- ✅ Check credit scores 3–6 months before applying
- ✅ Use a whole-of-market mortgage broker
- ✅ Budget 3–5% extra for purchase costs beyond the deposit
- ✅ Borrow comfortably below your maximum
- ✅ Get a proper building survey — never skip it
- ✅ Keep finances completely stable from application to completion
- ✅ Get a Mortgage in Principle before property hunting
- ✅ Calculate total deal cost, not just the headline rate
- ✅ Diarise your remortgage date and act 3 months early
- ✅ Get life insurance in place before or at mortgage start
Start with the Numbers
Use our mortgage calculator to understand your real monthly costs, total interest, and the impact of different scenarios — before you speak to a single lender.
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