Why does my 17 month old son all of a sudden want his blanket ALL the time?

He never cared for it ... then at 17 months he wants his blanket ALWAYS! He understands that he cannot bring it into the bathroom which is good. He feels comfort with it. He does not drink from a bottle, never did pacifier, fed first full year of life, does not go to daycare (we have Grandpa, daddy and/or Mommy with him at home).