Are the lizard that are getting into the house the House Geckos?
Do you have a lot of shrubbery around the house?
Have you had any insect problems in the yard?
What State do you live in?
I too am in Fl, and very familiar with the lizards. They are House Geckos. They are hunting food and the shrubery is what serves as a feeding ground and shelter for them. You can try some sticky traps that are sold at Target, Home Depot or Lowes. There is no real way to keep these guys out as they are nocturnal and will get in as you suspect from any crack or crevice they can. On a side note, they cannot tolerate cold, so keeping the AC tuned down will help keep them inactive and may keep them out. Some companies make sonic repellers, but I really do not have a lot of faith in them. Living in Fl, for all my life, I have learned there is no sure fire way to keep these guys out. You can try some of the suggestions that I have mentioned, but there is no guarantees. Joan