Returning a result based on an age in number of days

Hi chaps and chapesses,

I have a problem I wonder if you would be so kind as helping me with.

I have a spreadhseet to sort out and what I am trying to do is the following

Colum F has a number of days old e.g 154, what I want to do in colum G is add a category to this to count if the cell in colum F is 29 or under, 30-59 days, 60-89 days or 90 days plus.

Wasn't sure if countif or if etc would be of any use or how to go about doing it???

Thank you very much :-)