For me you advance if there is chance of game or slam - because I learned that opener is not supposed to say anything more unless asked or forced - but I am assuming you know how many tricks your partner is showing with their weak 2 (if you know that you can work out from your hand a hoped for total number - eg a weak 2 for me could mean anything from 4 to 6 tricks depending on various factors - then you look at your hand and decide - if you don't feel you can add much best to stay quiet). I have a very simplistic approach to bridge around how many tricks you think you can make. There is another situation if you think you have a better higher ranking 2 bid maybe show that
Its a remarkably simple game when you understand the point of it and how to score it
Maybe we need a little example. Suppose you know that your partner's bid means they think they have approximately 5 tricks in hearts, say, and you reckon you can add around 4 or more extra tricks then you consider advancing etc. That could involve bidding directly to game, asking more information using 2NT or even bidding another suit with more tricks or more scoring potential. Otherwise you pass. Sorry edited a minor mathematical error
* Disclaimer. This not may not work with your partner depending on what their bid means - does it mean they think they can make 6 or 4, maybe even just 3 tricks. It also requires a knowledge of suit rankings, how many tricks each need for game, what type of scoring you are playing etc - and the ability to count the trick potential in your hand and add up. But we aren't talking big numbers and complicated sums. Also your partner's 2X may not be a weak 2 at all
That is for you to know, not me