Arm, just profit. That goes for a 20 year hold as well. Just make sure you keep your purchase history printed because most brokers remove trade history after 6 years. You might have to prove purchase price to the IRS if they get antsy.
You only pay capital gains (or credited loss up to 3k per year) which can be thought of as your "profit". The only thing time affects is the "rate" of gains---shares held over 1 year qualify for the long term rate 15%--short term gains can go as high as approx 35-40% depending on your tax bracket.
Regardless of when you sell you will still be able to back out the purchase price and fees....the thing that gets me is when you lose money on a stock, the tax man puts a cap on how much you can loose but you have to pay taxes on ALL of your winners.