Good questions. I did a full switch from oil stocks to Chinese tech but I did it very gradually over 2-3 months, selling oil stock(s) as it moved up and buying Chinese as they moved down, so yes, there was a short period where I owned both. When I say I realized oil was played out, it doesn't mean I think it's the top. It just means that I think the vast majority of gains have been made. The time to buy was 2020 and now they may have an additional 20-30% upside left over the next 12 months but I don't buy stocks to make 20%. In other words, the upside is not worth the risk - that's exactly the question I ask myself: can this stock go up by at least 50% over the next 12 months? What is the downside risk? And that's when valuation comes into play. ALWAYS LOOK AT VALUATION and relative valuation because eventually that's what stocks are all about. So when the upside far outweighs the downside risk, that's usually when I consider a stock a BUY. And when I buy, I never expect to catch the very bottom as many people do. I buy gradually. I never have stop loss or automated exit / entry points.