on a scale of 1 to 10.....how difficult would it be to replace all drains in house? 1 being easy peasy and 10 being get a professional.

[Anonymous]

All drains are old metal and are corroded rusted and leak at some point. We are first homeowners and are ambitious to do diy....but we don't want to really mess things up. Suggestions? Hints? N e thing to help would be appreciated....GREATLY!!