Snorting cocaine has a duration of anywhere from 20mins-1hr (depending on quality, tolerance and each individual's body) followed by a very mild comedown, but mainly tolerable. you need much more cocaine this route.
Smoking cocaine in it's freebase form (aka Crack) has a duration "euphoria" for about anywhere of 5-15mins, followed by a crash and feigning feeling for hours, but the actual rush is about 20 seconds long, and the high can last up to 15mins. all you need is a tiny rock the size of a pea to get a euphoric blast and 15min high (quality depending, tolerance)
IVing cocaine, can last anywhere from 20mins-1hr (my experience on all this), its a way smoother high than smoking it, with a calmer comedown. beware of side effects lasting hours (paranoia, geeked, feigning) all it takes is .1 grams to get a nice ringer and high, Iving even 0.3grams can be proven to be fatal..be careful, you need to find a nice medium when dosing this ROA...if u do too little, u will be disppointed wanting more, if u shoot too much, u may get severe panic attacks and very uncomofrtable, and possible health risks...find the dose thats right in the middle