Advice about the lifetime of a rig?

Hello,
I am trying to build a rig with that hardware:
Asus PRIME H270-PRO soccket 1151
Celeron g3900, 1151
4GB ram DDR4
2X Cooler master masterwatt lite 700W
5X Sapphire Pulse radeon RX 580 8g oc w/bp (uefi) lite
5X USB 3.0 Pcie PCI-E Express 1x To 16x Extender Riser Card (Version 007).
The parts are on the way, i am waiting the risers, ebay order.

I want to know how long this ring will be working without problems (theoretically) ? Presuming 24h/7days?

Thanks