When my husband moved here from England it was extremely expensive for him to ship his belongings. So he decided to spend the money on shipping things that mattered to him, and not shipping any clothing. He literally came here with the clothes on his back.
It took me about a year before his arrival (we were engaged at that time) to shop for and purchase an entire wardrobe for him. I am the QUEEN of budget shopping, resale shops, and estate sales.

So trust me, this was not as expensive as you might think when stretched out over a year. (And I had a TOTAL blast doing it!!!)
Anyway - I made sure that he had the following:
Two weeks of underwear
One week of undershirts
Three weeks of socks
One week of jammy pants/boxers for sleeping & one bath robe & slippers
One pair of swimming trunks
One week of trousers (as well as three pair of jeans)
Two weeks of dress shirts
Two weeks of casual shirts (polo and T-shirts)
Two pair of shoes
Three sweaters
Three suits and one blazer
Since then I’ve increased the dress shirts to three weeks of shirts so I always have some at the cleaner, some on the hanger, and some ready to go to the cleaner. I don’t do his shirts any more, we take them and have them done. And also increased to two weeks of trousers.
He works in an office job that is business casual.
But, as someone already mentioned, it really depends on what works for you. This works for our crazy lifestyle which does not allow me a guaranteed day every week to do laundry and a lot of late nights, and never knowing if he is going to need to be more dressed up one day than the next for meetings or whatever.
Cleaning out the closet is a very good idea - don’t forget to donate!!
~Liza