Write everything down

Every variation — owner-requested or builder-requested — should be confirmed in writing with cost and time impact before the work happens.

Why builders dislike informal changes

An undocumented variation becomes a payment argument later. Builders who insist on written variation orders are usually the better ones to work with.

Owner-side discipline

Decide and stick to it. The biggest budget overruns come from the homeowner changing their mind on tiles, kitchens and lighting after first fix.