what does one do when he hears of a rabbi in his communtiy who holds differrently to other but is a reputable talmid chacham?
recently a rabbi in my town said it is permitted for a non jew helper to wash clothes in the nine days if it will lessen the burden on her. this is not the opinion of my familys rabbi
can one pick and choose which rabbi to follow when?
You are asking an important question.
A person should not pick and choose between rabbonim, and for a number of reasons. If you have your Rov, you should listen to him for all of his rulings, because when you switch Rabbonim, you might end up doing two things that essentially contradict each other. This is because Rabbonim often say the rulings that they heard from their Rov who they learnt from, and have adopted their line of reasoning, which effects the way the rule. This can cause that in one ruling the Rov will be stringent and in another lenient, and both rulings are because of the same reason. By jumping around between different Rabbonim, you will be doing two contradictory ideas at the same time. Secondly, it isn’t being honest with yourself. Why do we ask halachic questions, to get a heter from the rov to do what we want, or to know what H-shem wants us to do in this situation? (I hope the answer is the latter.) Therefore, if a person has a Rov, and he decided that this is the person that this person will decide the halacha for him, he shouldn’t switch to a different Rov, just because the psak that the other one gives services him better. It is important to add that this doesn’t mean that one is not allowed to ask another Rov, as there are numerous situation when one’s Rov can’t be reached etc., but in general a person should stick to his Rov.