AD, I find it a very good and profitable practice to put a standing sell order in on a long I buy. From a stock's chart, it is often easy to see the first major line or overhead resistance. I usually place my sell order just under it. I find that the first shot up to resistance reverses very quickly and the pullback can be significant. Unless you are lucky, it is almost impossible to catch it manually and you usually have to wait a couple of days for it to go back up there. Having a standing order gets me out on those spikes and allows me to re-enter on the pullback.
If you use IB as a broker your order is active through the whole pre and post market. I have had many outrageous and profitable sales in the pre/post market. I have had sell orders hit after hours a good 10% or more above the closing price allowing me to re-enter the next morning at the closing price.
I always put a sell order in immediately after I buy even if it is outrageous.