How do you avoid getting overcharged or stuck mid-renovation?

The contract structure is your protection, not the person's charm:

• Itemised fixed-price quote, not a lump sum. Every line (demo, MEP, tiling, joinery, paint) priced separately, so you can see what changed if it changes.
• Stage payments tied to milestones — deposit, on first-fix complete, on tiling complete, on handover. Never pay most of it upfront; a contractor funded at the start has no reason to finish.
• Trade licence + written scope, including what's *excluded*. Most 'overcharges' are really 'that wasn't in the scope' surprises.
• Retention — hold back a small final payment (5–10%) until snagging is done.

Get three itemised quotes and compare line by line — the cheapest lump sum is usually the one that balloons.

Retention saved me — held the last 10% until snagging, and suddenly the little unfinished bits got finished fast. Also: get variations (extra work) priced in writing *before* they do them, not after.

Paying in stages against completed work is the big one. A friend paid 80% upfront 'for materials' and the guy disappeared. Never again.