How often should I take an elderly person out of their bed so that they don't become bedridden?

If a person were in a nursing care facility they would be dressed and out of bed daily. Dealing with the emotions of caring for a resistant adult in home is far different than in a facility however. A facility would simply grab a couple extra nurses and get it done. While at home, resistance from the patient can wear a care giver down to the point of saying "forget it". We have found it helpful to contact my mother's doctor and having him "prescribe" things that we need done. Sometimes she responds more readily to an authority figure telling her what to do as opposed to her children telling her what to do