I am planning to re-do the 'cobbled together' plumbing in our home and am
considering PEX. I hear that PEX is easy to install (which would help us
when we have to run pipes up existing walls).

The existing system used 1/2" copper (and 70 year old galvanized iron pipe)
& was run in a 'straight line' fashion. e.g for the 'cold' line from the
kitchen sink, to rear outside tap, to bathroom sink, to toilet, to cold
water inlet, to bathroom tub, to hot water inlet, to the front outside tap.

I see one way to install PEX is with a manifold system - where 1/2" PEX
pipes run off of a manifold to each appliance. Apparently that method
allows for less 'shower shock' - and, if you use individual appliance
shut-off's - allows for servicing individual appliances.

The only troulble with it is that we see is the cost of the manifolds and
the individual shutoff valves. We very seldom have to turn the home water
off for repairs so we think the individual shutoffs is kind of overkill.

Instead of the manifold system - could we do it in the 'straight line'
fashion - using 3/4" PEX? Or is there something we are missing?