@thetjs, the trimming decision is primarily driven by how "toppish" the price looks. The extent of the trimming is driven by the portfolio weightage - the more overweight it is, the greater the trim. With the market volatility in recent months, I've worked out that I get antsy when a position gets to 10-11%, which is my start point to consider trimming.
I prefer to trim over a few days/week to capture whatever upside there might be before the price reverses. Sometimes I get a better price, sometimes a bit less. If the position has bullish momentum, I will still trim in small chunks, but more frequently and as the price makes new highs, eg. EOS, to capture more upside.
Proceeds from the trim goes into the cash pool for redeployment to whatever else. Buying decisions will be driven by how much cash there is. So the trimming and buying decisions are completely independent of each other.
Have decided to take this approach to ensure I actually force myself to take some profits and minimise wipeouts of paper gains from my previous buy-hold-long-term-come-what-may approach. I have also found that from an emotions perspective, the fact that I have trimmed at higher levels makes me it much easier for me to buy back at lower levels, provided, of course, the dip has been on no bad news ...