Kawaida ubora wa saa unahusishwa na mambo mbalimbali kama vile saa inavyoweza kuzuia maji. Shirika la Kimataifa la Usanifishaji (kwa kifupi ISO) limetoa vipimo maalum vya saa zinavyozuia maji.
Saa zaweza kugawakugawiwa katika makundi mawili makuu kuzingatia kizazi; saa za zamani (analog) na saa za kisasa/za [[dijiti]] ambazo ni za [[Elektroni|kielektroni]].<ref>{{Cite Web|url=https://greatwatches.nyc/digital-vs-analog-which-is-better/|title=Digital vs Analog Watch - Which is Better?|author=Great Watches NYC|language=en-US|date=17 March 2018|work=Great Watches NYC|accessdate=10 July 2018}}</ref>
Pia zinaweza kugawakugawiwa katika makundi saba kulingana na mtindo na utenda kazi:
* saa za kujiendesha (automatiki) - saa zisizo hitaji betri
Mstari 23:
* saa zisizo na mengi ''(minimalist watches)'' - saa zisizo na marembesho mengi
* saa za quartz - saa zinazo tumia teknolojia ya quartz
* saa za kivazikimtindo - saa za kisanaa zinazolenga mvuto wa kipeeepekee
* saa za kifaharifahari - saa zenye bei ghali mno zinazoundwa kwa kulenga matajiri na mara nyingi huendana na vitu vya fahari kama magari na simu
* saa zinazotumia [[nishati ya jua]]
* saa za [[wanariadha]] - saa za kisasa ambazo, balimbali naya kueleza muda, pia zinapima mpigomapigo waya roho[[moyo]] na mambo mengine muhimu ya kuzingatiwa na wanariadha wanapofanya mazoezi<ref>{{Citation|last=Eric|first=|title=The Athletes Guide to the Best Triathlon Watch|date=2018-08-11|url=https://www.approachingfitness.com/best-triathlon-watch/|work=Approaching Fitness|volume=|pages=|language=en-US|access-date=2018-08-17}}</ref>.
