The reason you were told to “get something with at least 30% DEET” is because under older guidelines this was true. Simply put, the higher the percentage of DEET in a given formula, the longer and more effective the protection from insects. Until the introduction of Sawyer Controlled Release Insect Repellent, we would have recommended Sawyer Maxi-DEET 100% DEET Insect Repellent for the skin. People often confuse concentration with dosage. Lower “dosages” of 100% DEET or DEET mixed in a Controlled Release lotion or even a standard lotion work better than alcohol-based sprays.As an added measure, you may still consider 100% DEET for times of extreme bug density. However, the real question is not how much DEET you start out with, but how much of the active ingredient, DEET, is available at any given time (even hours later) to repel those nasty mosquitoes.Skin repellent with Slow Release Technology–Sawyer Controlled Release 20% DEET Insect Repellent uses sub-micron encapsulation to entrap the DEET. An effective and long lasting insect repellent for use on the skin is a slow release technology that keeps the repellent on the surface of the skin much longer than other formulas. This provides for slower absorption and extended effectiveness against biting insects. The Sawyer Controlled Release Insect Repellent formula provides this type of technology in a formula that is both effective and very comfortable to use.