I'm 39 and I still get stuff from Santa and the Easter Bunny. I'm not kidding.
Our rule is that Santa only goes to one house in a family (easy to continue after me and my sibs are grown cuz I have the only child) so if you aren't there then your gifts get left at the house we were all at and you get them later (ie I mail my sister her stuff if she can't fly in to celebrate).
I advocate honesty in every single circumstance I can think of...... except Santa, the easter bunny etc.
My daughter is 10 and I have no idea if she actually believe in Santa and the easter bunny, but she definitely "believes" in their spirit - which is the most important part. She would NOT plant doubts in a younger child if one came into the family because she sees how excited everyone gets. Plus, she benefits. "if you don't believe - you don't receive".
It was the year I graduated from college that my mom explained she had been contacted by Santa and he needed some help with gifts - she suggested we become Santa and we each all start getting everyone else in the family gifts. At some point after dinner on Christmas eve we each put "our" Santa gifts in the stockings (or easter baskets) so no one knows who gave what - or if anyone gave at all.
For Easter - our routine is similar to Christmas, actually. We each have a basket and we leave treats for the Easter Bunny before bed. When we wake up we see if we have been 'visited'.
But we also hid eggs for my daughter around the house until she was probably 8 - those little eggs that you can open and hide stuff in.... some were empty, some had little jewelry pieces or stickers and 1 egg had $20.00.