How do you ensure, that you can checkout the code into Eclipse or NetBeans and work there with it?
Edit: If you not checking in ide-related files, you have to reconf
The smart ass answer is "by doing so" - unless you aren't working with multiple IDEs you don't know if you are really prepared for working with multiple IDEs. Honest. :)
I always have seen multiple platforms as more cumbersome, as they may use different encoding standards (e.g. Windows may default to ISO-8859-1, Linux to UTF-8) - for me encoding has caused way more issues than IDEs.
Some more pointers: