Archiving Ticket Requests Types - Implications of leaving tickets or ticket types archived?

Are there any performance implications from having lots of archived ticket request types?  Should they be deleted?  Should the associated tickets be deleted after the request type is deleted?

We are working on cleaning up and reorganizing our Web Help Desk ticket request structure and will have lots of request types getting archived (that whole process I understand), but should we eventually be deleting the old archived request types?  Is there any downside or performance issues with letting them linger in the database along with the older tickets using the archived request type?

I remember speaking with WHD technical support several years back and they described leaving things archived in WHD as creating and or breaking "connections or links" within the database that can cause database instability, errors, corruptions, or just general performance issues.  I wanted to know if this is still the case or things have changed with newer versions.