How much disk space / bandwith do you need for your average forum?

I'm trying my hand at self-hosting and I found a free piggyback option that offers 15GB of diskspace and 100GB/month of bandwith. Sounds as good as it gets, especially in comparison to other options, but do you think it's enough once my forum hopefully grows? I'm not expecting anything huge, but, well, having some activity is the point of having a board. Should I be ready to look for an alternative, or is that enough to run a board in the medium term? Not sure how much is "too little" and "enough", so I am asking you more experienced fellows.

 

That should hold you for a good while. One thing that will help is not allowing folks to upload images. Set this so they can only use URLs instead. Doing this will save the disk space.