maybe different beauty standards, from my life in China I remember men keeping fairly long nails before trimming them and many keep one fingernail like on pinky extra long to use as tool (you don't wanna know the most common use)

for me it's 2-2.5 weeks before it become uncomfortable to type on keyboard or use touch screen, dirtyness is not really an issue, just wash hands/nails properly (it probably helps to do office job from home instead manual labor)