There are two separate answers here and they run on different clocks. One is about drainage. The other is about time.
Drainage first. Contact your provider if there are any signs of infection: redness, increased warmth, or swelling around the wound; more drainage than before or drainage that is yellowish or cloudy; bleeding; odor; fever or chills; increased pain. Also watch for drainage that is increasing, drainage that is not decreasing after 3 to 5 days, and drainage that becomes thick, tan, yellow, green or smells bad.
Most of that list is comparative. More than before. Increasing. Not decreasing. That means the thing that makes it usable is some sense of what the drainage was like a week ago — how often the dressing needed changing, and what color it was.
Time second, and this is the part that gets left too long. You may have a non-healing wound if it has not started to heal in 2 weeks, or has not completely healed in 6 weeks. Foot ulcers due to swollen legs and poor blood flow are one of the common types of non-healing wound treated at a wound care center.
Two weeks without starting to heal is a referral conversation, not a reason for more patience.
At a specialist service, the team will examine and measure your wound, check the blood flow in the area around the wound, figure out why it is not healing, and create a treatment plan. For a leg wound the blood flow check is the important one, because it decides whether compression is the treatment or the thing to avoid.
If you are already under a service and the drainage has changed, that is a call between appointments rather than something to mention at the next one.