How long does the mosquito repellent sticker works?

The performance of the stickers depends on the conditions listed below:

The breeze
Since citronella repels mosquitoes with the scent, it usually performs better when the outdoor condition is not windy. In indoor condition, the stickers could be effective up to 72 hours. When used outdoor, it could last between 16 hours to 24 hours depending on the breeze. A Strong breeze will dissipate the citronella oil faster and cause a drop in performance.

The number of mosquitoes
If you are walking through parks or area where mosquitoes are sparse, having 1-2 stickers would provide sufficient protection. However, if you going on a trip through the tropical rainforest where the mosquitoes are abundant, 3-4 stickers are advisable.

Placement
Always place the stickers close to the area where your skins are exposed. If you are wearing long sleeve and short pant, it would make sense to have the stickers on the shoes, pant, and shoulder instead of the sleeve.