I had 3 in 3 years and 2 months- similar to RuffleTheAnimal.Mine are 4 1/2, 3 and 19 months. It is very hard work, especially if you have no or little family support. We never stop and it is becoming a real juggling act getting my DD to school and my DS to pre-school with a younger toddler in tow.
Three is a nice number of children as mine play together well and you get the baby/toddler stage over more quickly but it IS feckin hard work and you can't do things like relax when the baby is asleep, for example.
If I had my time again I would have a bigger age gap as having three so close has also left me with some nasty complications which means I require surgery next year.
I am SAHM although I would love to work part-time teaching but my wages would never cover the childcare costs and so we manage on one wage in London which is very hard. We could never manage the childcare issue with three. It would be completely unworkable unless I stayed at home.
At the moment, we never get a moment to ourselves and this can be quite depressing and a real strain on our marriage. Getting a babysitter for 3 is just not possible for more than a few hours. We go out together about once or twice a year if we're lucky.
I'm really looking forward to all of mine being school age simply because my DH and I are so exhausted. Like others on here, I am very house bound - it is an absolute mission to get them all ready to go out but if you stay in, they wreck the house, so you can't win!
I personally haven't found 2 to 3 easier than 1 to 2 as you're restricted in what you can do for so much longer with 3. The practicalities of having 2 toddlers and a young girl are difficult too- negotiating walking/sitting in the buggy, shopping, trips out and the cost of course! Not just in the short term but in the long run- is very expensive.
Ask me again in about 4-5 years if having three is beneficial! I'm sure I'll come out the other side and say 'yes'
If you have three, my advice would be have an age gap of at least two/three years between each one so you can pay them individual attention and not be so overwhelmed with the demands of early years childcare as we have been.