Re: How long for Little People?
My 3,5 and 8 yr will still play with our Christmas sets when they come out. I even bought a new Christmas set because ds loves them so much. With my kids, around 2ish they lose interest in the little people but it picks back up once they enter a new level of play (3ish). Given the choice by then they'd ask for something other an little people as a gift but put little people in front of them and they'll be happy with it.
My 5 yr old would technically love the princess castle that just came out. But I won't buy it just because there is other princess stuff she'd ultimately rather have. At 2.5 I wouldn't think twice about buying more little people stuff.