Most contractors are probably not surprised when the homeowner wants to do some of the work of the remodel. Their reactions can vary. Some will not want to risk a negative effect on the overall quality of the work if they believe you cannot do the work up to their standard. Some will be completely open to letting you do what you want. (You can expect this to be clearly stated in the contract). Still others will work with you to determine your skill level and make suggestions about types of work you might do that will not negatively effect the quality of the finished work and will not result in you being in their way as they do other tasks.