I recently re-entered the baggage dating market (as opposed to dating baggage market) when I tore a seam on my suitcase while un-sticking it from a cramped overhead bin. But seeing how I buy luggage once every 10 years, might have undiagnosed OCD, and know a thing or two about the travel industry, I spent way too much of a long weekend calculating which bag would maximize my space, while still fitting airlines' size restrictions.
Let's save you the headache.
Although the International Air Transport Association's recent proposal for "optimum-sized" bags hasn't become standard yet, once airlines adopt this policy (they probably will), your old bag will cost you $25 every time you check it. Not ideal.
Right now, most US airlines allow bags that measure 21in x 14in x 9in. But guidelines vary -- especially overseas. Low-cost European carrier RyanAir, for example, allows bags measuring 21.7in x 15.7in x 7.9in (55 x 40 x 20 cm), while rival EasyJet allows bags that are 22.04in x 17.72in x 9.8in (56cm x 45cm x 25cm). Non-low-cost carrier KLM, however, restricts bags to 21.5in x 13.5in x 10in. These are just a few European carriers -- not even accounting for other continents -- and already there are enough measurements to make Bob Vila's eye's glaze over.