I have always considered myself to be a mosquito magnet. I have to carefully plan my outside activities and yard work to limit being bitten to death by voracious mosquitoes. This means that I have to wear long sleeves, use an effective insect repellent, and do most of my work before 4 PM when the mosquitoes seem to worsen.
If anyone was going to get a mosquito-borne illness, such as West Nile virus or even malaria (even though I do not live in a malaria area), I would be the one. Malaria alone — transmitted by mosquitoes — kills over a million people annually across the globe. I often feel that if I were in a 40,000 seat arena, I would be the only one swatting mosquitoes away, but I know I am not unique on this planet. Many people feel that they are unusually molested by these pesky insects.
I have been a DEET fan since I first heard about it in the early 1970s. Commercially-available (and highly effective) products like Off Back Woods or Jungle Juice have a liberal amount of this chemical; usually about 30%. My old lab technician used to make his own and give it to me. His was a 100% DEET. DEET is an FDA-approved ingredient, but even I worried about using the homemade 100% one.
Over the years, I have personally tried other insect repellents, based on articles that I have read, or rumors that I heard. It is amazing the list of home remedies and advice that people will freely offer when they see you waving away at mosquitoes or scratching at your many bites. People inherently mistrust science and unnatural chemicals, and really like natural remedies, whether they are proven to work or not.
One of the first rumors was that mosquitoes do not like vitamin B (vitamin B1 or thiamine). Vitamin B1 deficiency (beriberi) is very rare in the United States. I did not take supplemental vitamins, but I thought I would give it try. I found it worthless. I tried Avon Skin-So-Soft, but that did not work either. Consumer Reports tested it a few years ago and did not find it effective either. However I did smell nice and my skin was so soft.
Natural remedy books were recommending a variety of aromatic herbs, like basil, lavender flowers, lemongrass, thyme, and garlic. One source suggested that I rub my skin with a half a cut onion. Obviously, this would not go over big in a crowd or at work. I found references for vanilla extract (smells better than garlic and onion), peppermint oil, and a variety of essential oils like tea tree oil, pennyroyal oil, red cedar wood oil (which also is supposed to repel leeches and rats!), and eucalyptus oil.  I read that catnip essential oil was also an effective repellent for mosquitoes, but unfortunately, it seemed to attract cats.
Vicks Vaporub has always been a source of alternative uses. My grandfather actually ate it (bad idea), thinking it prevented colds and cured sore throats. One source, probably a grandmother (or my grandmother) suggested that by smearing Vicks all over yourself, mosquitoes (and others, obviously) would be repelled.
Testimonials touted the attributes of using Bounce Fabric softener, Lemon Joy dishwashing detergent, and Listerine (or Listerine mixed with beer and Epsom salts).  Apparently beer-drinkers are bothered by mosquitoes less than non-drinkers, but I am not convinced this is a chemical effect, but rather one of intoxicated indifference.  Mosquitoes are also attracted to people who eat bananas, so should we give them up?
I find it troubling to pooh-pooh many of these home remedies, since I have not personally tried them. I am not about to rub onions all over myself, spray Listerine, and drink beer just to prove a point. If any of these remedies work for you, then by all means use them. Like all unproven remedies, please restrain yourself from recommending them to others without a personal disclaimer. Herbal oils do show some limited (and short-lived) repellency, but DEET is still the most effective.
I tried a few of those battery-powered devices that are supposed to repel mosquitoes. They give off a high-pitched whine like a mosquito, perhaps signally other mosquitoes that I am not available. I even wore two of them. They did not seem to help. So, short of training a frog or lizard to stand guard on my shoulders, or have trained bats hovering around me, I feel doomed to be feasted upon. I have not tried those new mosquito-repellent shirts infused with a chemical repellent, but if I head for a jungle sometime in the future, I will be wearing one.
What really attracts those annoying (female) mosquitoes to some, but not all of us? Pregnant women (as if there were other types) excrete more heat and carbon dioxide than non-pregnant women. Genetics may be playing an undiscovered role. Someday, researchers may discover that our mosquito attractiveness lies in our genes.
Studies have shown the moisture, warmth, body odor, and exhalation of carbon dioxide attracts mosquitoes, as well as lactic acid that is excreted with exertion. When I work outside in the hot weather, I have all of these things. One study found that people with Type O blood attract mosquitoes more (I am Type O). For some reason, people with high cholesterol tend to be bothered by mosquitoes. Since my cholesterol is fine, this is really the only thing that I have going in my favor.
It is late afternoon and I am now in my house. Hungry mosquitoes are banging into my window trying to get at me, not unlike the zombie scene in Night of the Living Dead. I did get a few bites, even though I tried to cover my skin surface with DEET. I have a bite near my eyelid and one near my watch band — two areas I may have missed. I do not have West Nile Virus, Yellow fever, Dengue fever, or malaria yet, but I am not giving up my protection.