I noticed my son (now 2 1/2 years) needed interaction when he was about a year old. I would take him to the play areas at the mall or a restaurant and he would just stare at the other kids like they were aliens. He was transfixed by older children we saw at the stores! At about 16 months, we enrolled him into a daycare on MWF. It was difficult to find part time daycare programs, so I got lucky. I got him in at about 9am and picked him up at 3pm, so not really a full day. Besides, at that age, he napped for a good amount of that time.
After he got used to going to leaving mommy, he loved going to school. His interaction skills grew by leaps and bounds. He was feeding himself easier. Daddy & I felt he was more confident in new situations, like huge family parties and going to the park. Just after he turned 2, we enrolled him full time at the same school. BOY! Did his language just explode! He was talking like crazy! Lots of singing and dancing and trying new things on his own. He's potty trained now, without too much grief. It helped to see other kids going in the potty. Daycare was definitely the right thing for our son.
In the end, I do think it is SO IMPORTANT for babies to stay home with a parent for the first year at least, if that's possible. For development, bonding, feeling secure...but when you think your child is ready, he/she also needs to explore and develop on his/her own when the time is right. Only you & Daddy can really determine when that is.
I will tell you that leaving him was SO HARD. It broke my heart every time I dropped him off, I missed him at home, I lived for Tuesdays & Thursdays when he was home with me, and he seemed to be growing up so fast! But a year later, seeing the funny, outgoing, silly boy he is...I really have no regrets.
My #1 piece of advice is to VISIT, VISIT, VISIT any place you plan to enroll him in. My first choice was our church's MDO program, but when I visited, they were wiping noses with the rough brown paper towels and kids had access to brooms, dustpans, and other cleaning materials. Another place I visited had dirty dishes and left overs (open jug of milk, half eaten bananas) from morning snack sitting in a cart at the back of the room HOURS after snack. Easy for young hands to get to! Keep an eye on ratios and interactions with adults. They gotta love kids to do this all day!
Good luck with your decision. It's far from easy, but you'll do the right thing for you and your family.