I am mother to twin daughters, one of whom has two year old twin boys, and the other who has just learned that she, too, is expecting twins! Any hard work and exhaustion is more than compensated by the sheer joy they bring. My grandsons are mischievous and full of energy, and I would struggle to look after them every day, but I am happy to muck in and help with bath time, pick them up from the childminder occasionally and do my share of babysitting.
If I can give a couple of tips, it's to keep bringing along packs of nappies to help out with the family budget. They go through huge amounts, but I find I can help by looking for nappy offers and using my doubled up Tesco points to replenish nappy stocks. Also, assume your daughter will always be experiencing extreme fatigue in the first few months, so provide as many opportunities as you can for her to recharge her batteries.
The happiest times are bedtime stories, funny twin conversations, enthusiastic cuddles, and sitting round the kitchen table making cookies and chocolate cake. Messy but hilarious.