There are many different factors that can affect how long your balloons will stay afloat for. This can depend on the quality and type of the balloons, the ambient temperature of where you have the balloons but in general terms the float times are as follows:
Latex 11” 9-10 hrs
Latex 11” With Hi-FLOAT - 48hrs
Foils 18” 3-4days (brands with XL (Extra Life ) will float approx 3 weeks.
Bubbles- 3-4 weeks