Bathing/grooming dogs

Question
Hello ! Steven, We own two dogs.A retriever/sheperd mix and a Dalmation/Blood hound mix.My wife pesters me about how we should be bathing our dogs every few months,but I dont really feel that it is all that necessary since they are both kept indoors 80% of the time.
How often should a dog be bathed or groomed ?
Outside of bathing them due to a flea infestation,is it really that important ?
Our retreiver has only had one bath in 6 years and seems to be doing fine ?
Your Thoughts ?

Thank's Steven for taking the time to answer !

Answer
Considering thier breeds it is fine to bathe them every few months.  You don't want to bathe them to often though or it will cause dry sikin plus it is not good for them to be bathed all the time.  I would bathe a dog more thatn once in 6 years.  Once or twice a year even may be fine, but if you want to bathe them once evry couple months thats fine.  I bathe my 9 dogs every 2-3 months.