Buy and hold, is this still a good strategy.

I am typically a long term investor, I learnt this from my father. He would buy a share in a company and pretty much hold it forever. This was a very long time ago, and the strategy seemed to work. I tried this a few years back, and noticed it worked for your typically blue chip stocks, because after a big correction, or even a crash they seemed to recover. But it seems these days there is always a time to sell, and knowing when to sell is more important than actually buying the share. Perhaps t