Are we talking deicing or anti icing-
2 very different subjects with there own requirements, though both are normally carried out at the same time that is certainly not always the case in all parts of the world or airports.
Deicing is at it says-removing the contamination from the aircraft-thats it.
Anti icing however is a different ball game with many variables, ambient temperature, weather conditions-ie rain, sleet, snow etc, temperature and mix of the fluid being applied and of course the type of fluid-there not all the same-this will directly effect the "hold over time"...can be minutes to hours...once the hold over time has expired you have to "reapply anti/de icing fluid again if the weather conditions/aircraft require it.
And afterwards you need to wash the aircraft as its leaves a sticky mess...