JOB SECURITY- How To Make A VBA Script Expire

method for making a VBA script expire?

I.e. it will only work for a specified time and requires the author of the script to renew it at a given point?

I want to be able to do this to strengthen my position as an independent contrator financially...and copy protect my work from unwanted exploitation

Some ideas:
1-MSG box requesting a pre-defined password to renew the time for the script to work along with contact info for the author

2-Ability to define # of days, months and or years the script will work

3-Ability to define the # of days, months and or years that a MSG box warning of pending expiration will appear

4Ability to define the # of days, months and or years that the renew will extend the use of the script with multiple pre-defined passwords allowing different lengths of time extention! Perhaps an encryption method allows you to in another excel sheet (say the comfort of your own home) generate at will a password that will extend a scripts life for 3 months?! They contact you again, and again you generate a "random" password that will extend the original script

5-Anti-hacking measures, using MS's built in security

This might be a useful way of extracting monies over time, for the use of a script you provide....pre-set