I built a 48x24 rf with a 4 rich warmer cabinet. I built a steerable cart with swing shelves, and added some extra dampers between all the chambers. I bought the plans from this site to avoid mistakes and used all new material.
I was working full time so probably averaged 10hours a week on it- and I am pretty meticulous so probably took me longer than most. All told, I’ve got $2000 and 6 months in it.
I completely uunderstand your concerns. My pit runs perfectly and I built it to last a lifetime. I feel it was worth it but not at the expense of family time. Most of my work was done after the family went to bed as I would head out to the shop for a few hours. A new baby is precious and a miracle in its own...don’t miss the memories.
It really depends on what you want. A UDS can be built in a day, Frank has kits that you can assemble in a few weeks. Having plans and everything CNc cut will save time If you decide to build from scratch.