|Here is the easiest formula:|
This works on the principle of descending orders of most strict criterion to least strict.
Think of it this way, It checks to see if the person has been employed for 4 or more years first, if so, it returns "15" for 15 days. If not, it checks to see if they have been employed 2 years or more and returns 10 if they have. We do not need to worry about the upper limit here as anything 4 or more years would have been satisfied by the first "IF" statement. This proceeds on with the 1 year or more and finally if no criterion are met, it returns 0.
Note that I did not use absolute cell referencing as I assume that you will be filling the formula down multiple rows for each employee.
Please let me know if this makes sense or if you need more assistance. Thanks!
IT Desktop & Network Consultant - MOS Master Certified, MCP, MCSA, MCITP - Windows 7, CCNA Certificate Pending, A+, Network +