I'm an only. I had everything I wanted growing up. Clubs, holidays, I was the star of the show. I'm likely in line for a sole large inheritance. I'd give it all up to go back and have grown up with a sibling.
We had DC then had DTwins. So there's a whole bunch of us. DH is low 6-fig salary. I've not worked until the last few months to save us on childcare. I'm lucky to have walked straight in to a well paid part time role now.
We're also lucky to be in the position of an early inheritance to put towards a house, and so we can get somewhere lovely and big. But I don't drive the car I want, we don't take nice long haul holidays. My clothes could be nicer. I could run the bank dry each month on clothes/toys/books/stuff for the house but I'm a smart shopper and use charity shops and FB for sale and search carefully for real bargains. I often resell on eBay for more than I paid. We tried Butlins hotel for the first time when DTwins were 2, thinking we'd stay one night and leave in disappointment. Loved it. But that's because for us, it really is the more the merrier.
Christmases are everything I never had but longed for. I had a huge pile of toys to over compensate that I had no one to play with. Now, with DC plus DH and I the pile is enormous, just because it's that many more people. DTwins are oblivious that their massive bundle of paw patrol was £20 from FB for sale.
We have no family childcare help, and lack of childcare has been the bane of our lives. Until very recently, I was almost going crazy stuck at home with "mum...mum...mum...Mum!" 12 hrs a day, which has been relieved by the now enormous nursery fees. There have been some real low points for me, mental health wise, where DTwins have been relentless and there's no one to give me a break, and I haven't had a day or night off since the day they were born, (with the exception of one night in hospital after I had an accident) and it's been four years. DH often does not finish work until their bedtime. They have eased up in recent months, and my new job is a welcome break. It's much better.
Another thing that may sound daft, is sick days. If I'm sick, I'm off work. But if child 1 gets sick I'm off work. Then when they get better but child 2 catches it, I'm off work. Then child 3 gets it. Then I catch it again off child 3...you get the picture.
The admin for more than one child soon adds up
Multiple dental appointments. Doctors appointments. Parents evenings. Clubs. School forms.
Having more than one child is so much more than the money. You have to really want a larger family, or I think you could have regrets, or even resent that you are more restricted. If you're the type who needs new everything, and recoils at the idea of a lovely Feather and Black bed frame for £30 because someone else has slept in it, then unless you have a big income, multiple children will be expensive.
Once you get the childcare ages out of the way, it's manageable if you make smart purchases, and have a good income. Having to spread our finances, time and resources over multiple DC can be tricky at times. For me, it's absolutely worth it.