For example, right now banks and petroleum are very active and hot. Every sector goes through phases of hot and cold.
Timing is everything in the market.
I invest in biotech, but stick to the philosophy of buying stocks that go up in price and have good value. Right now for example, I feel GZMO is one biotech with good value and is underpriced. It is only underpriced because this sector is not hot right now. I would use this time to accumulate good valued biotechs and be patient for them to have there day. We are in a big bear market now and it is not easy to find hot stocks consistently.