This is so interesting - it's such a personal thing isn't it?
I was a freelance writer and lifecoach before having DD so was used to working from home office and managing my own time. Found it very, very tricky when I put her in nursery for two full days a week when she was seven months, having just about kept things going around her naps until then (She was in a routine from early on - I couldn't have done this otherwise). She wasn't sleeping and was overtired and miserable, and I had PND. A horrid time.
Everything improved when I switched to Mon-Thur mornings at nursery when she was 11 months - we were both happier and have a great rhythmn to our mornings and our week, and every afternoon after her nap we have time together, plus Fridays. So I drop her at nursery at 8.30, pick her up at 1, she sleeps until 2.30-3pm and then my work finishes when I hear her stirring on the monitor. This really works, for me and her, financially and emotionally. It wouldn't suit everybody.
I was inspired by my own experiences after having DD to focus my life coaching business on new mums - I set up The Mother Mentor to help mums work out the best answer to this very question for them, as well as other areas of the highs and lows of new motherhood.
There is no set answer - every mum and every family has different needs, desires and pressures, and it's about finding out what works for you. I think it is always possible to find a way of making the balance work for you - it might take some time, and I don't think the guilt ever completely goes away, though!
I don't know if things would have been easier or harder for me and DD if I had been an employee rather than running my own business and under all the different pressures and decision that that brings.
Now everything is going like clockwork, of course I'm expecting number two this summer... and feel rather more confident that I can probably make things tick along with two pre-schoolers after a few months off.