Thing is Sean your list of expenses spread over a ten year time span is simply laughable, sorry. It's list alright but it's the bare minimum you might envisage what your costs might be. In reality they'll be drastically different to that. Equipment breaks down and needs replacing. Better equipment comes on the market and we upgrade. Your estimates for how long your equipment will last is generous to say the least.
If you took your figures to a bank, let's say you were looking for a business loan, they'd laugh you out of town with those projections.
No they wouldn't as most if not all businesses base their expenses over a 5 to 10 year period as its the only way to get an accurate
figure.
Your could buy a new 4040 membrane this year at £250 but it doesn't mean you will need that expense every year so you
would need to tell the bank what they should cost you if they work for as long as they are intended to work which is about five years.
You might only get one year if your unlucky but you cant know that in advance.
I'm going about eight years and have not cut corners on any equipment that Iv bought and I can honestly say that WFP is costing
me less than £500 a year.