I have absolutely no idea why God invented mosquitoes. I cannot see they do anything useful at all apart from being a tasty snack for lizards and tarantulas. However, living in the tropics they are all over the place and you would think you would get used to mosquitoes and not let them bother you. You don’t. When I first arrived in the Dominican Republic around 12 years ago, when I was bitten, which was often, I would get a large lump and it would itch like crazy for days. However I think your body must build immunity as now when I get bitten I just get a little lump which goes after an hour or so. I still don’t like them though.
In the early days I would spray anti mosquito spray all over my body from head to toe, just like all of the tourists, but if you live with mosquitoes all year round, besides being very expensive, I can’t see that it does you any good to cover yourself with chemicals day after day.
So you try and have preventative measures such as screens on the windows and mosquito nets. Also good are mosquito coils which you burn. They are especially good outside in the evenings under the table to stop the little critters munching on your ankles...