What is Layout / size?
Full-size (with numpad), TKL (no numpad), 75%, 65%, 60% (shrinking key sets).
Short answer
Spreadsheet users: keep the numpad. Check where arrows and Delete went on small boards.
Layout / size when buying a mechanical keyboard
Full-size (with numpad), TKL (no numpad), 75%, 65%, 60% (shrinking key sets).
Why it matters: Smaller boards free desk space and bring the mouse closer, but drop keys you might need.
Look for: Spreadsheet users: keep the numpad. Check where arrows and Delete went on small boards.
Full Mechanical Keyboard buying guide