Senators will be limited to maximum of 12 years of Senatorial service. But will be of sufficient length to get legislation passed and projects completed and to maintain continuity on various committee functions,as well as groom new members.
By extending Represenatives' term from 2 to 4 years
and a maximum of 12 years of Congressional service, Represenatives would have the same benefits as Senators
plus the added benefit of campaigning once every 4 years instead of 2.
Setting term limits will reduce long-term costs and benefits associated with seniority/longevity. as well as cronyism.