Direct answerPump settings and temperature control have a large effect on cost.
What to check first
Repair leaks that cause constant top-up.
The existing pool, property access and equipment condition can change the answer. Record what is happening before adjustments are made.
What affects the work
Keep the filter clean.
A clear scope should separate inspection, repair and optional improvement work. This makes quotations easier to compare.
When a site visit is useful
A site visit is needed when the answer depends on pipework, water loss, structural movement or the exact equipment installed. Photos can narrow the likely cause but cannot confirm a concealed fault.