i got given tiny sizes by well meaning people (who had never had kids) so didn't buy any 00000 myself.

i spent my pregnancy buying 000 and 00 in opshops. mainly transeasonal, some summer, some winter. but all natural fibres. babies overheat easily, so i avoided synthetic stuff.

the sizes i bought more of, well my answer to that was, if you get to the stage where everything that fits your bub is
- in the washing basket to be washed
- waiting to dry
then you prolly need more of the current size.

i got more use out of two piece items, than the all in ones.
i got most use out of the things that did up easily, at the front. Hated the clothes that had back fastenings. anything awkward to do up - i ditched. did not have the energy to waste on badly designed stuff.

my bub arrived in a heatwave, so nappy, singlet and muslin wrap was all she really needed for first few months. i was unprepared with baby sunscreen and what to dress her in to make her sunsafe for that first summer. I now find out, it's unadvisable to take newborns out in the sun for first six months, so maybe it's a blessing that my PND was so bad, i didn't take her out anywhere anyhoo, (except for hospital visits we were driven to).

if you're having a July bub, a pram snug might be useful to you. it's like a blanket that zips onto the pram bit the baby lies in.