Each paper has its own physical properties that contribute to the overall sharpness of the printed image so a one-size box definitely doesn’t fit all.
Other labs especially mini-lab printers, apply a heavy amount of automatic sharpening during printing which we avoid as it can over-sharpen and introduce unwanted effects not visible on-screen.
It is best for clients to apply sharpening in Adobe Photoshop and check the file at 100% print size view to make sure is it adequately sharp and no digital artefacts have been introduced as a result of the sharpening process.