Im the higher earner. I had my part of the bills covered before going on leave both times, so I managed to save on leave.
Buying stuff before really depends on how much you want to spend - id you want to spend £300 on a travel system you can, similarly Ive seen them for over £2k!! i think with my first we spent about £2000 on travel system, spinny car seat, next to me cot, the bigger cot, clothes, my maternity wear, nursery furniture, etc. I would say we did get carried away. It was good quality though - with my second i genuinely didnt spend a penny (other than nappies) until he was about 6 months! You can get a lot on marketplace and vinted, if you want to keep costs down.
I managed to save my spending money (and more due to no commuting costs), for the second half of the year while i was on full pay for the first six months. I budgeted £500 per month spending - lunches, classes, clothes for us both (and i didnt spend it all, not nearly!).
I would say your food shop is going to go up £30ish per week on average in the early days (nappies, lotions, potions, wipes, formula, weaning food, breast pads, pads, etc - all the allergens can add a bit on). Shop around for nappy and wipe deals.
my heating bill went up both times.
Big outgoing to factor in now are childcare deposits and the first months bill, i unknowingly didnt factor it in fully during my first mat leave and had a shock! Had it sat there with baby two
it’s worth sitting down and plotting what you have coming up/spend in a month, putting aside a realistic birthdays/christmas pot. You’re going to want your haircut at some point. Have a look on some websites and write down the sum of 7 vests, 7 babygrows, 3 outfits at each baby size. How much baby sensory and a costa is twice a week. That sort of thing. You will spend less, in my experience and friends, but its helpful having a range/trajectory written out.