I say “stuff” because these guidelines will travel beyond a particular category. So, to keep it simple, we’ll call it “stuff”.
First, in order to date items that are Czech, you need to understand a bit of history.
Czechoslovakia did not exist prior to 1918.
Czechoslovakia was formed mainly between two people, the Czechs and the Slovaks. Thus the name. In the 1920’s as well as into the 1930’s the name was referred to as Czecho-Slovakia. Although not an absolute, looking at how the name is spelled may give you the clue you need to identify and date and item.
Also, from 1920 until 1938 Czechoslovakia’s formal name was Czechoslovak Republic and is sometimes written as an acronym CSR.
During WWII when Germany invaded and occupied Czechoslovakia, the country of origin on some items was listed as Germany instead of Czechoslovakia.
Czechoslovakia ceased to exist as a country on January 1, 1993.