Don't do it unless it's a known SOP for a particular airport.
An example. Departure frequencies can be different depending on how busy the adjoining airspace is, or even which runway is in use at the departure airport.
Aircraft gets airborne and goes straight to (what he thinks) is the departure frequency. However, due to lack of traffic ACC has changed the frequency to increase the sector size, plus Approach needs to work traffic anyway to de-conflict from arrival. End result - aircraft is left hanging on a frequency which isn't in use, whilst Tower is trying to contact aircraft to transfer them.
In addition - at several airports Tower is responsible for verifying and validating your squawk before en-route transfer. Can't do that if you've changed frequency.
What I'd like to see is the next frequency given as part of the clearance ".....after departure contact........" if an automatic change is required, leave it out if it isn't. Takes away the guesswork about this that is starting to creep in.