How long does it take for beginners to paste Yan Zhenqing's diligent tablet, or to what extent can it be changed?

There are no hard and fast rules for this, and you don't have to follow him. The key is to see if this book is your favorite font, find a copybook you like very much, first observe its meaning, find out the stroke direction, the thickness of the next stroke, and the font structure, and then compare it repeatedly with the original. Speaking of the same as the original, you can draw inferences, but it is easier said than done. Without patience, diligence and talent, it is difficult to achieve anything.