A home extension or major renovation is one of the few projects where the architect chosen affects both the final result and how smoothly the entire process unfolds, making selection worth genuine diligence. Ask to see completed projects of a similar scale in person where possible, rather than relying solely on rendered visuals, since renders often flatter a design in ways the finished build doesn't quite match. Discuss their approach to budget management upfront — a good architect designs with cost realism built in from the start, rather than producing an ambitious design that later requires painful compromises once actual quotes come in. Clarify exactly what's included in their fee: initial concept design, detailed drawings, planning permission handling, and construction oversight are often billed as separate stages, and understanding this structure prevents surprise costs later. Ask how they handle disagreements with contractors during the build phase, since an architect who stays actively involved through construction, not just design, tends to catch issues before they become expensive to fix. Compatibility matters too — a renovation can take months, and working comfortably with someone whose communication style suits you makes the entire process considerably less stressful.