For kids, here is a rough guideline of what I try to do. I try to do it in a rotation, so you aren’t buying everything at once, so they get new clothes through out the year and it allows for kids to grow out of clothes without suddenly most all of their clothes being to small.
4 sets of summer weight pjs
4 sets of winter weight pjs (try to get ones that can also double as thermal underwear on really cold days)
6 pairs of short socks
6 pairs of longer socks
12 pairs of underwear (this allows for ‘accidents’ and such, you don’t want to run out of underwear)
10 pants (2 that are on their way out, they can have holes or what not, they are the ‘messy’ play pants, 3 that are older but still decent that can be used for play and school, 3 that are new that are for school only, 2 dress pants {tan and navy}) If any of these pants are the kind that you zipper off the bottoms and then they are shorts, that is a bonus.
10 t-shirts, as with the pants, some should be old for play and some should be good for school and at least 3 should be long sleeved
7 shirts for school, 2 of them should also work for dress and go with the dress pants, 2 new, 5 still in good condition {then later in the year I will buy them 2 more shirts and get rid of 2 that are too small or no longer in good condition they may end up as ‘play shirts’}
3 play shirts
2 decent sweaters
4 sweatshirts (2 old and 2 newer)
2 swimsuits (an older one and a newer one)
5 pairs of shorts (fewer, if some on their pants have bottoms that zipper off)
They need footwear and coats, but that is dependant upon the weather in your area.
Of course, there is room for variation depending on your needs, how frequently you do laundry, etc, but this is the general rule of thumb I go buy. As for shopping right now, I will go through the clothes and see what is still good for school this year. Then I will replace about half of what I need now and about half in a month or so after they start school. Most likely, this is what I will end up buying now:
4 shirts
3 pants
2 t-shirts
In a few months
1 sweatshirt
1 sweater
1 shirt
1 pair of pants
1 winter pj
1 pkg socks
1 pkg underwear
2 t shirts
I hope this helps.