How To Convert Days To Proper Format

i use to get the difference between two dates i.e user's signup date and todays date in order to check that user has atleast logged into his/her account within 45 days otherwise i ll delete the account.

i calculate the difference by using datediff function for days upon current date and account created date. it displays the results in no of days say 32 days or 134 days

but i want to have it properly formatted in format like:

in case of 32 days
1 month and 2 days
that i can do by myself

but how to handle following situations:

if there are 30 days in month
if there are 31 days in month
if there are 28 days in month
if there are 29 days in month

how to handle these situations.