7.5 yr by the time baby arrives. I am glad of a big gap. I think anything 4+ years would have been good. My twins were extremely difficult babies and toddlers. None stop crying and puking 24/7 between colic, reflux, asthma, eczema and constipation which caused them to have absolutely horrendus nights meaning they were 14 months old before I managed more than 1 hour broken sleep per 24 hours, if I slept at all. There was the odd 1.5 hour total but very rare. 3 yr old before I managed to get more than 1-3 hours sleep. Always had a brilliant and strict routine and even 2 sleep specialists gave up on them. 4 yr old before they started sleeping past 4am and they were 5.5 yr old before both slept thru the night. There has been absolute non stop every waking moment every day of screaming, fighting, shouting, competing to get 100% of my attention on themselves 100% of the time, back chat, trashing the place, tantrums and all the rest until they were 6 yr old no matter how they were disaplind or what rewards were offered and I was never inconsistant, always stuck to my guns and they didn't get away with things so I am very glad we are now at a stage they have calmed down and also them being in school full time means I can put just as much attention on new baby as I did with these when they were little even thou I did work full time until my twins were 3 I was with them all day 4am-4:30pm then worked 5pm-1am most shifts with 1 or 2 days shifts.