How to use condoms, and everything else you need to know Reviewed It's National Condom Month. Condoms are pretty cheap, at most pharmacies, and when used correctly, highly effective at preventing pregnancy and sexually transmitted infections. If you always use one Original Lubricated Condoms + Spermicide Classic Condoms Trojan Do spermicide condoms work? Pros and cons Can Condoms Cause Infections? Understanding the Link Happy V Do spermicide condoms work? Pros and cons