My house's water pipes are in need of replacing. From leaking joints to been cut into and rewored from Galv to copper with out dialetric connections which are now starting to show failure. Not to mention there are no shutoff valves other then the main and one on each side of the water heater.

So I want to rerun the lines in either Copper or PEX. My question is should I do replace how they are now. Goes from main to kitchen, then bath, etc or should I run home runs for each room back to main and back to water heater?

Which is most effecent?

I am thinking about replacing the water heater at same time as well as correcting a leaky shower valve/laundry tub at same time. So this is going to be a long weekend job. Would like to run the new get it all set then just have to cut the items in one by one after I cut out the old. So wife and kids are only kicked out for a day or two rather then the whole weekend.