Comic strip formatting?

[JoeRunner]

I've been drafting a comic strip for a newspaper syndication portfolio (although actual success is unlikely), but I have a question. Some comic strip collections I have read say that comic strip panels had to be the same size (so they could be printed horizontally or vertically), but many comic strips I see in newspapers (or syndicated strips also published online) don't consistently stick to this. Is it an outdated guideline, or does it just decrease the number of newspapers able to print the strip, or something else? (I've tried searching online, but people generally don't care much about newspaper strips compared to comic books, webcomics, etc.)

[spadedigsbutts]

The same size requirement is likely a carryover from older methods of newspaper comic printing that have been largely replaced in the digital age. Before the technology we have now, a comic artist would make the strip, and then a larger version of it cut down into several pieces would need to be sent to the newspaper in question so they could manually arrange them in anticipation for print. Most old school low tech printing methods still get used, it’s just mainly by smaller artists to print zines and such for cons. I think some syndicates still use the old methods but it’s probably mostly digital now.