Latex balloons filled with helium generally last 10-12 hours. For an additional charge, you may add hi-float to your latex to give them extra float time, ranging from 3-5 days.
IF YOU PURCHACE HI-FLOAT BALLOONS FROM US, YOU MUST REMOVE THEM FROM THE BAG. WE DO NOT REPLACE FLAT LATEX.
In general, all mylar (foil balloons) last between 3-5 days depending on where they are kept (indoors or outside), and the temperature. Cold air causes helium to condense but will reinflate once the balloons are brought back to room temperature. Very hot weather will cause helium to expand, which will result in a popped balloon.