DH and I are foster carers with docs and from what we've experienced they prefer placing a child younger than your oldest. We have Tyson with us til he turns 18 (final court orders) and just found out that Kiara will be with us til she turns 18, final court orders. In the process of adopting Tyson who's been with us since he was 3 weeks old. We did respite care and found it challenging as both times the boys were older than Tyson and younger than Ard, causing a bit of conflict.. I'm so glad we have a girl to even things out. We are taking time out from respite care for a couple of years til kids get older, than may go back too it as its alot for Arden and Tyson to handle. However the good thing about respite care is you know when its going to finish, usually, gets complicated sometimes..I've found the carers support groups handy!