Unfortunately it can never necessarily be worth it. You need to ask yourself "What makes me truly happy"
This is simple on one level but you have to think on another. If you die, did you enjoy what you did with your life thus far, are you satisfied? Running has always been there for me, given me time to think, vent, and just have fun, but in the end it is all just for self satisfaction.
I struggled a lot with it this last year and my training has gone up and down, it is nowhere near where it was but I'm trying to regain some of it so I can at least be sub*blank* again (to avoid letsrun time criticisms).
Unless you're elite, running will give you some cardiovascular benefits, better bone density etc. maybe some prize money if you're decent and do the road racing scene but it is more the memories you get from it that you have to cherish or how it can keep you a balanced person.
I know when I quit for a while, I had the worst time concentrating and people were telling me I seemed unhappy, I didn't think it was running until I got back into it some.
You're asking others here "Is it worth it?" When it comes down to: Do you think it's worth it? is that how you ENJOY spending your time moreso then other things? and at 29 is it STILL the way you want to spend a lot of your time?
Good luck with figuring things out at this crossroads, it can be tough, it took me a good 6-7 months and I still debate about it but I also understand myself and my running better.