What is the best size?? f pipe, can? Use to plumbed the whole toilet,bathroom and kitchen?

What is the best size?? f pipe, can? Use to plumbed the whole toilet,bathroom and kitchen? More details please!
Single family home? Condo?
What pipe sizes are you looking for? Drainage? Water pipe? Slab or basement unit?
Will this work be contracted out or will you be doing the job yourself? Do you have a set of plans you could scan in? Back to you, Tom