Can't vouch for anyone else, but for three weeks I took:
1 pair jeans
1 pair shorts
3 t-shirts
1 polo neck shirt
1 summer shirt
3 pairs underpants
2 pairs socks
This was as well as my riding gear:
Dianese vented jeans
2 pairs Nike anti bacterial shorts
3 tech t-shirts
Dianese body armour
race shirt
fleece
Sinisalo enduro jacket
3 pairs summer hiking socks
pair of cheap waterproof trousers
Alpinestars waterproof jacket.
And a tube of travel wash.
HTH
Mark