What happens if you do nothing
When a fixed rate ends, your lender does not ring you up and offer you a new one. You roll onto their standard variable rate, which they set themselves, can change whenever they like, and which is usually a great deal more expensive than anything you would be offered as a new deal.
Nobody chooses the standard variable rate. People end up on it because the end date arrived while they were busy, and by then the switch takes weeks they have not left themselves.
Why six months
Most lenders will let you secure a new rate up to six months before you need it. That gives you a deal in hand and takes the deadline away entirely.
It also means that if something in your circumstances has changed since you last borrowed, a new job, a business, a dip in income, a change in credit history, there is time to find the lender who reads that situation favourably rather than taking whatever your existing lender happens to offer.
Securing early does not lock you in
This is the part people do not realise. Booking a rate early does not commit you to it. If rates improve before completion, we check again and move you to the better one where the lender allows it.
So the downside of starting early is nothing, and the downside of starting late is paying the standard variable rate for however many weeks it takes to sort out.
Staying put is sometimes right
A product transfer with your existing lender is often quick, sometimes needs no valuation and no legal work, and occasionally beats everything else on total cost. We treat your lender's offer as the benchmark and only recommend moving if moving genuinely wins.
What we will not do is assume the answer either way before running the numbers.