Trimming Yews

I have two large yews in the front of my house, near the porch. They are well over 6 ft. tall and large around. I keep the new growth neatly trimmed, but I'd like to have them cut back to about 1/2 size, if not totally taken out. Can this be done? I also have a large rhododendrum on the front corner of the house that is huge, too huge, and I'd like to get that cut. Some say wait till after it blooms in the spring. Any advice? I'd like to have a landscaper come and take everything out and replant, but I'm getting quotes of $3,000 and wonder if trimming may be an option? I think the yews were planted when the house was buillt in 1963, and I just bought it in 2003. Thanks.