I find it to be a useful exercise, especially if your holdings are in ISA.
Personally I am not sure if I would re-buy because everything ran up so much, but in the same time I am not selling which seems illogical.
I don’t really think that it’s helpful to ask that. You have much more information now, so your choice would be heavily influenced by hindsight bias. Hindsight bias is an incredibly strong bias, so I wouldn’t lose sleep over why I did something back in the day when I’ve got the jnformation that I have today.
You have X money in the market in stock A, B, C.
If you had X cash instead of ABC today would you still buy ABC because ABC will net you best return on investment or would you buy DEF?
If you would rather buy DEF then you should sell ABC immediately, right? (assuming there are no tax implications or penalty for selling)