Anyone doing any math with time?

Say I wanted to time out a form. I call my foo sub and want to time this form out in approx (dynamic) minutes. Say I call the (VB time function) and try to say MyTimeOut time = (VB time function) + (dynamic) minutes. Then in the form I can ease the system strain by setting my timer to check the actual time every 65 seconds for (VB Time function) to => MyTimeOut vice an incrementer variable.

I have tried a number of methods and it apears that i have missed the boat. I Realize that this is a little academic :) but does any one have any ideas.