The bulging, twisted veins you can see are usually a sign that valves deeper in the leg have stopped doing their job.
The fine red, blue or purple clusters on the legs and ankles. Often cosmetic, sometimes painful, and occasionally a clue to something deeper.
The veins in your legs carry blood upward against gravity. When their valves fail, blood falls back and pressure builds, and that pressure is what causes the damage.
Legs that ache, swell or feel heavy by the end of the day are worth explaining, even when there is nothing obvious to see.