They won't pay tax on spares apart from on purchase but they will have to depreciate the asset reducing the EBIT and reducing free cash.
Accountants will want to minimise assets to maximimse cash & EBIT
I don't remember in my many years in the senior Finance positions personally wanting to minimise assets to maximise cash...........especially if you have an efficient stock turn ratio or sales to captal employed ratio. etc.......it was more the management team/corporate objectives may drive short term solutions to balance sheet measurements often for the sake of appearance and individual bonuses than sound custodianship. Everyone blames the accountants when often its the failings of the rest of the management team, that the accountants pull out of the mire.
Well known aspect of decision theory states, tell me how you will measure me and I will tell you how I react, in essence incentives like bonus payments set on achieving eg departmental budgets, profits etc will often distort management behaviour in such a way they then achieve the said target often taking tactical short term decisions at the expense of longer term opportunities
