.......a long time. Tips to measure and mark accurately. An article in the current issue of POPULAR WOODWORKING I think it is, posits that measuring is in most cases a waste of time and effort and better results are achieved by marking a piece directly from its intended location. Measuring only when absolutely necessary to establish a starting point. Always measuring from the top and/or the left side of rhe datum piece. Anyway, here’s the URL for some tips about measuring and marking.
https://www.familyhandyman.com/woodwork ... /view-all/Remember don’t force the fit, get a bigger hammer