Installing a faucet. Where do I need thread tape?

My old kitchen had a dishwasher that received its water supply from a line tee’d off of the hot water line supplying the kitchen faucet. When you opened the sink cabinet, you could see one single hot water line coming from the wall and into the cabinet, then the line tee’d off to supply hot water to both the faucet and the dishwasher. I understand that plumbers now rough in the plumbing so that there is a dedicated line coming out of the stud cavity for both the faucet and dishwasher without the need for a tee inside the sink cabinet. Just wondering if this is really necessary. I’ve never heard of any new code that states that this is mandatory. For the newer method used by some plumbers... regarding where the dishwasher’s hot water line comes out of the stud cavity, is the placement dictated by code? I’m just trying to figure out how many inches above or below the faucet line should the dishwasher line come out of the stud cavity.

Hello! we had a clog in our sewer line. The plummer came out to root out the sewer line, however, we did not have a sewer clean out valve. He just cut a hole in the line and told us to install a clean out valve ourselves. since that time, we have had standing water in the yard. We realize that the hole in the sewer line is to blame. Besides installing the clean out valve, is there anything else that should be done. we are first time homeowners of a 100 year old house, and have very, very little knowledge about home repair. thank you for any advice- suggestions you can provide!