It's a fine line here, and if you buy and sell on COMC and eBay you you know this! One good game and you're BIN price sells on either site. You think you may have missed out on a few $. Maybe. But maybe listings drop back down in 2 weeks and if that game didn't happen you're listing would've been sitting there for another 6 weeks.
I guess it comes down to what you're in this hobby for. And it can vary wildly - have a main PC and have a combination of flipping other stuff to fund your box breaks and main PC, have a main and a side PC and trade or sell the other stuff to help other PC and set collectors out, flip everything after box breaks. I've probably seen and done it all so I Don't really criticise much anymore lol. You need to be actively watching every game and updating your prices hourly if you want to stay in touch with the Lin effect, it's tough.