Buy core items in bulk and top up as you go. Sizes shift, staff change and garments get discontinued. Holding six months of stock in the popular sizes is sensible; holding two years of it is money in a cupboard.
A rule of thumb we use: hold enough stock to cover your worst-case new-starter lead time, nothing more. If it takes you three weeks to hire and onboard someone, six months of core sizes covers turnover comfortably without tying up cash in garments that might get discontinued before you use them.
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