Agree with CIVIL who said
''I found waiting six months was the easiest option - you're in the swing of babies then and enjoyed a long period of just doing one thing before having to introduce a different thing (e.g. food).
Plus, it's much nicer seeing a baby actually sitting in a high chair rather than lying down receiving food. ''
My own experience was similar. I had 6 months on my radar. Firstly for DD's likelyhood to be receptive to the process. Secondly because of the iron level at this age. I started gradually a few weeks before.
Prior to that DD was EBF and although she liked playing with anything she could grab she clearly couldn't sit up straight or swallow easily so I waited until 6 months. It was a breeze; lumps, chunks, purées nothing was rejected. Sleep fine, few minor adjustments to pattern required. Took two weeks of extra washing up, laundry, buying more fresh food etc....
At 4 months I would have found it hard to do this, especially when out and about. Hopefully DD will always be a good eater.
I found the NHS weaning information very helpful. The books were too complex and had rather too many recipie ideas that were labour intensive. I have found common sense works best in terms of what to feed and how much.
Interestingly though the NHS website states this:
??Vitamins-
Vitamin D is naturally present in only a few foods such as fortified margarines, eggs and fatty fish. It is also made naturally in the skin when it is exposed to gentle sunlight.
It is sensible to give all children vitamin drops with vitamins A, C and D from the age of one to five years old. Breastfed babies and babies drinking less than 500ml of infant formula milk per day, should begin vitamin drops at six months, or earlier if advised by your health visitor or doctor. ??
I was not advised this my NHS heath visitor. I see her monthly and she is aware of EBF