First of all, the 5 year requirement is probably a business requirement from
some financial people or legal department.  The question becomes what
granularity of recovery they want.  I presume you run daily backups.  So,
lets say for a minute that all data revisions must be kept for 5 years.
That would require up to 5 x 365 versions and an expiration of 5 years.
Now, if you are doing INCR type backups remember the files only get backed
up on every change.  If you are doing SELECTIVE you may want to reconsider
to reduce the number of backups.

Now for the piece you may not have considered.  The business may also need
to keep the deleted versions for 5 years.

Too often as technicians we start compromising the amount of data kept
without having the proper knowledge or backround to make the cut-back
decision.  Let's take the example of a medical record.  When can I cut out
some of the information?  The answer is never.  Bank records are similar.
Engineering changes are similar.  Manufacturing inspection records are
similar.

The best decision is to go to the business and let them determine the legal
and business requirement.  Design a solution and tell them what it cost.

Consider your old paradigm.  After 1 month, all the daily revisions are
lost.  After 60 days, you have only the monthly revision snapshot (what good
is that?).  Ask your business the right questions and you will be able to
design a matching solution with TSM.  The closest you can probably get to
what you were doing before is Backup Sets.

Your email should be put in a different management class.  That is easy to
do, depends on the email system and which TDP you need.

Good Luck.