CRB checks do last 3 years, I had to have them done in my previous employment (care worker) lucky enough my mum is the director of my previous job so I can still get them done (due now) and it cost me about £50 for full one, I do know that when my mum employes new staff even if theyve had a CRB done in the last 3 years it counts for nothing and a new one needs doing, also if your only doing externals of nursing homes etc you dont need one but of your doing any internal windows to residents of the homes rooms (bedroom) the manager/director etc by law has to get you CRB checked, internal of nursing home communal areas, restaurants etc doesnt count.