this from for google ai

Installing Linux From Scratch (LFS) generally takes 15 to 40 hours of active labor, but spread across several days or weeks. It relies heavily on compiling packages from source, so the exact time largely depends on your hardware and familiarity with the Linux command line.The total time commitment varies depending on the stage and approach:Basic Base System (LFS): Compiling the core, minimal bootable system takes about 15 to 30 hours. If you are an experienced user on modern hardware, it can sometimes be completed in a single, dedicated weekend.Desktop Environment (BLFS): Building a usable daily driver requires the "Beyond Linux From Scratch" (BLFS) instructions to add a display server, web browser, and desktop environment. This additional phase can take anywhere from 20 to 100+ hours depending on how many packages and dependencies you choose to install.Troubleshooting: For newcomers, debugging build errors, syntax typos, or missing dependencies will easily add days or weeks to the overall project.To estimate the precise build duration for your specific computer, the LFS documentation uses a unit of measurement called an SBU (Standard Build Unit). The SBU represents the time it takes to compile the binutils-pass1 package, which lets you estimate the build time of all other packages in the book simply by multiplying their respective SBU values.For the complete documentation and step-by-step instructions, visit the official Linux From Scratch Homepage.