Generally speaking, a leakdown test is performed after one does a compression test and finds low compression in any/all cylinders. The leak testdown test is then used to pinpoint the cause of the low compression, be it valves,rings, or gasket.
If one has good compression, a leak test is not needed..

Rather than hot or cold , the main concern on a compression test is to have all the plugs out when cranking with a fully charged battery to assure rapid starter rpm and also have intake air available by opening the throttle air source. It is also a good idea to disconnect the fuel power/line so no fuel is fed to the engine when the test is performed [ this usually means simply remove the pump fuse , if electric pump]
It is also wise to number the plugs as they are removed so you can get a read from them , knowing which cylinder they came from. [ ie .. an oily plug from a low compression cylinder could indicate a bad ring in that cylider]