A spreadsheet that looks fine on screen often prints badly — wide tables cut off, or text too small to read.
Page Layout tab → Print Area sets exactly which cells print. "Fit to 1 page" scaling shrinks wide data to fit one printed page width, instead of splitting it across several.
Ctrl+P shows exactly what will print before it prints — always worth checking once, since Excel's grid rarely maps to a printed page as cleanly as it looks on screen.
Page Layout tab → Print Titles → Rows to Repeat at Top keeps the header row visible on every printed page of a long table, instead of only the first — the single most useful setting for a multi-page printed spreadsheet.