Cooling off between visit - Parents on Family visa

Hello Forum,

I am holding ILR and my parents are here on 6 months family visitor. Is there any specified time period for which they need to stay outside UK before allowed to come again ?

Cheers
Lin

Roughly six months. They should not be spending more time in the UK than in their home country (6 out of 12 months as a guide) otherwise they are likely to be viewed as 'residents' and not 'genuine visitors' and can be refused entry.