Saving member settings for modules. Best practice?

[TSP]

I have some settings for certain modules where each member will be able to define their own. 

In IPS 3.4 I usually saved these in members_cache, but that's no longer used in IPS 4. 

I'm hesitant to add my own database columns to the members table, since it eventually might become quite a lot of them. So what's your suggested approach for this? Should I create my own settings table? And what about member settings I wish to be more globally available? (And not just in a certain area)

I would love your input on the best practice on this. 

[bfarber]

Are these on/off (1/0) settings, or do you need to store textual values?  You could add a bitwise column (you could also use an existing one, but there's always the possibility we will end up needing to use the bitwise flag you choose if you try to use an existing column) which would allow you to store multiple 1/0 settings in a single column.

[TSP]

In this particular case it was a list of forum ids. I ended up creating my own settings table for members.