The best time to lock in prices is after you have a clear written scope but before any work starts or materials are ordered. That means you and the contractor agree on what exactly will be done, in which rooms, with which broad level of finish. Vague descriptions like “redo kitchen nicely” are danger zones; they leave too much space for confusion later.
First, talk through the plan. Then ask for a detailed quote that breaks down labour, materials (even if some are provisional), and any extra charges like debris removal. When the quote makes sense to you, get it in writing along with a timeline and payment schedule. Only then should you treat the price as “locked”.
If you sign or pay without clarity, changes and “extras” will suddenly appear mid-way, and costs creep up. On the other hand, remember that locking in price doesn’t cover design changes you request later. If you decide halfway to upgrade tiles or add new work, it’s fair for the contractor to revise the cost.
So the sweet spot: finalise scope → get written quote → clarify doubts → then lock price. Not before, not much after.