If you work on systems where you have the occasional 2x spike in traffic or planning for 2x capacity requirements in the future is easy then you don't have the same problems as suhail has.
I work in advertising for example. We could have 10 partners at 1x. Add 10 more and be at 1.1x or 2x, then add a large partner and be at 7x. There isn't a pattern to when we get partners from any of these groups but when we get them they need to go live as quickly as possible and sourcing and prepping hardware in situations like that isn't feasible. Nor is it feasible to have hardware on standby for the occasional 7x partner since you don't know when they are coming along and they could end up being a 10x partner.
I work in advertising for example. We could have 10 partners at 1x. Add 10 more and be at 1.1x or 2x, then add a large partner and be at 7x. There isn't a pattern to when we get partners from any of these groups but when we get them they need to go live as quickly as possible and sourcing and prepping hardware in situations like that isn't feasible. Nor is it feasible to have hardware on standby for the occasional 7x partner since you don't know when they are coming along and they could end up being a 10x partner.