How long after lipo do I need to wear a compression garment?

I recommend following up with your Doctor about their protocol regarding compression. I have my patients wear compression for 3-6 weeks straight then overnight for 3-6 months after their procedure. For liposuction after care, I recommend adding hyperbaric oxygen and lymphatic massage along with your compression to help decrease swelling. To improve your final results, I also recommend adding vanquish for further fat removal, exilis/venus legacy for skin tightening, cellutone/z wave to make the skin smooth, remove scar tissue, and improve the skin’s appearance. Best, Dr. Emer

Surgeons recommendations will vary on a number of topics. The quick and easy answer to your specific question...is garments should be worn as long as your plastic surgeon recommends. That being said, most will recommend 6-8 weeks of compression (some longer/some shorter). Some physicians will recommend a transition to part time usage half way through this period.
The garments are important for controlling swelling post op and mitigating the risk of fluid collections while obtaining a smooth contour.
As always, discuss your concerns with a board certified plastic surgeon (ABPS).