Service charges are fees paid by flat owners for the maintenance of common parts of the building or estate, like lifts, hallways, or gardens. These charges can be variable, and in some luxury high-rise developments, they can be quite substantial. Lenders take service charges into account as they form a regular financial commitment for the borrower. If service charges are high, they could affect the affordability calculations made by the lender, potentially reducing the amount they're willing to lend or influencing the mortgage's terms. It's crucial for potential buyers to be aware of service charges and factor them into their financial planning when seeking a mortgage.