Well not really, but if you don't practice, you may find your skills getting rusty! I had taken a few months long break recently from astral travel, and have throughout my time practicing magic taken several such breaks, one which lasted at least a year or so. And I've found that the longer the break, the harder it is (at first) to get back into astral travel, pathworking, etc.
I find it interesting that this should be the case. Everytime, I'll feel a little sketchy for a few days getting back into it, then will get back on my astral feet so to speak, and start ripping around the astral, meeting interesting people and other things, and making an attempt to learn from some of them.
Of the subdivisions of magical practice, evocation and astral projection are definitely two of the most versatile areas (for me. Others may disagree, or find other areas more useful.) There is so much that can be done with these two disciplines, so much that can be learned while doing them, both about oneself, and the world/universe around him or her, and about magic itself.
Sorry if this has been a little rambly.