The 3.0 Epic level handbook allowed one of the seeds (Life I think) to be used to modify the age brackets, now by taking a lot of penalties which you can afford to do as the spell isn't going to be cast very often or in combat you can easily apply some big modifiers to the age brackets, and is a nice solution because it doesn't benefit the long lived races any more than the short lived ones.
It also means that the person does still age and die, it just takes much longer for each age bracket to come into effect.
e.g. A 40 year old Wizard casts the spell (or has it cast through some means) and then very slowly ages to reach Old Age at say 153 and probably dies at around 200, unless he gets another casting with a higher effect which would probably prolong his time in the Old bracket.