Whether you can live through your renovation depends on two things: which rooms are out of action, and for how long. A bathroom is two to three weeks without washing, a kitchen four to eight without cooking, and both are livable with a plan. What each route really costs, including the posts nobody budgets.
Put the living plan in the money plan: the budget planner deserves a line for eating out, laundry and temporary arrangements, and the budget tracker shows what it actually costs while it runs. Timing the build itself: how long an extension takes.
Usually yes, if it is your only bathroom you bridge two to three weeks without a shower: a gym membership, family nearby, or a hired portable shower. The toilet is the real constraint; ask the builder to keep one working toilet connected as long as possible, and put that in the plan, not in hope.
Four to eight weeks without a kitchen is the honest range. A temporary kitchen corner (microwave, air fryer, kettle, cool box, washing-up in the bathroom) makes it livable; the hidden cost is eating out, which at family scale runs to hundreds of pounds a week if you do not plan against it.
When the work touches the whole house at once: rewiring with floors up everywhere, structural work, damp treatment in every room. Weigh the rent against the speed: an empty house lets trades work faster and sometimes cheaper, and a shorter build claws back part of the rent. Ask your builder to price both scenarios; it is a normal question.
More than anyone expects. Seal doorways with taped sheeting, move what you love out of the work zone, and accept that fine dust travels anyway. Anyone in the household with asthma or a lung condition is a real reason to plan sleeping elsewhere during demolition weeks.