I don't think that there is anything wrong with letting a winner run. My advice is to take some profits when it stops winning. You may not have enough conviction that the run is over to sell all of the position, but it is time to stop being over-weight.
When I first bought a gold fund... it has to have been 3 years (or so) ago... I thought it would be a trade (I hadn't owned a gold fund for a decade)... and I am sure that some traders have traded in and out of it many times since I first bought it. I have been holding through a remarkable secular bull market.
Energy will probably be the same thing. It could be a sector that stays hot for a year or two, but it could also be the best sector investment for a decade... it has to beat out REIT's and gold, though.
In the late 90's, I was over-weighted tech... but not nearly like the Janus folks - the best fund family according to some for half a decade. I own very little today. A few years ago, I let my REIT holdings get over-weight... it too had a great run for 3-5 years. Today, I still have some - about 4%, but less than half what I had at the peak.
Today, I am over-weight in energy. Given the fundamentals, I will be over-weight for at least a few years, it could be longer!
Gary, I probably won't be the first one at the exit door. I have tried to stay fairly passive in my sector bets and not be constantly trading them. I do believe, though, that you need to be able to walk away from over-weight sector positions. If you tend to fall in love with your investments or look at your portfolio once a year (or less), then this is no place for you (the figurative "you") to have an over-weight position. Sectors have to be traded... the frequency of the trades is one of investment style. If you are not a trader, limit your pure sector bets to 5% of your portfolio and enforce that limit.
I always talk about major changes in my portfolio, but I don't make many specific buy/sell recommendations based on my personal portfolio. I really do try to customize my advice to the requestor, and not just advise everyone to do what I do. That would be pretty poor advice imho. If I post "Is it over for energy?", then you want to pay attention. For example, my personal portfolio has changed in the last year (a lot). I have begun buying individual stocks and sector ETF's/CEF's quite a bit... I have reduced my reliance on mutual funds. I've talked about what I see as being the weaknesses of mutual funds. You haven't heard me talk about the specifics much. It would be wrong for anyone to go out and just buy the stocks I discuss here. Would if I sell it and forget to tell everyone...
erryl