i do that. i have some that have been held for several years that i don't touch, and some that i trade in and out of, usually using options.
some stocks are better for trading and others are better for investing. QBE is a prime example of the former IMHO. great to trade in and out of, but personally, there's no way i would want that thing in my long term portfolio. conversely, something like WOW is a great stock to hold long term (again, my opinion only - this is not a recommendation) but not ideal for trading - consistent, dependable results, but doesn't usually have significant, rapid moves.
just make sure that if a trade doesn't work out, you exit it, don't get tempted to "turn a trade into an investment" - the reason you're getting into a trade is to make a short-medium term punt on something, maybe an earnings report, moving the stock quickly (in either direction), the stock is not necessarily a good long term investment, so you don't want to turn it into such.