I just had revision rhinoplasty and they had to graft some cartilage. How long is the recovery time?

It varies. The recovery time will vary depending on how extensive your revision surgery was. If it was done only for a minor problem in the tip or along the bridge, then it will heal quickly. More involved revision with grafting as you mentioned will take longer. Most swelling will be gone in 4-6 weeks but it will continue to improve for at least one full year. Be patient and discuss this with your surgeon.
Months. While you may heal from the operation and look reasonably good in a short time (2 weeks), the results of rhinoplasty are measured in months if not years. The nose will continue to subtlely change over the next year or more.
Revision rhinoplasty. Revision rhinoplasty takes at least one year to fully heal. Depending on the amount of work done it may take even longer to get the final result.
2-3 weeks. Most people take 2-3 weeks to recover. Swelling may persist for up to 6 months.