Asymmetry is the tell here. Swelling in both legs by evening suggests a system-wide cause — ordinary venous insufficiency, long days upright, medication effects. Swelling that clearly favours one leg says the problem sits somewhere specific on that leg's drainage route — and when that leg is the left, one candidate jumps up the list: May-Thurner syndrome, where the left iliac vein is pinched under an artery on its way back to the heart.
That's also why this question sits in the check's "left-side signs" cluster alongside clot history: a squeezed iliac vein causes one-sided heaviness and swelling for years before — in the serious version — it causes a DVT. Catching the pattern at the heaviness stage is the point.
If you answered yes: note which leg and whether the difference is constant or end-of-day, and say it in those words at an assessment. One other possibility your other answers help sort: single-limb swelling that includes a puffy foot leans towards lymphoedema instead — a different drainage system, with its own checks.