DirecTV, Dish Network and others are always having free previews of Cinemax, HBO, etc.
Does Spectrum ever have free previews?
That depends if the host channel is doing a national free preview or only a selected market free preview. This website below lists up-to-date information about every provider when they are having a free preview:
Go to the right-hand side of the screen to choose Spectrum. Today, February 27, 2018, it says that many may get a free HBO/Cinemax preview this weekend.
Note that the information provided is not guaranteed, may vary by market, and is subject to last-minute changes. If it's not a national free preview, the station has to work it out with the TV provider to offer the free preview.
I was wondering the same thing as it has been forever it seems since the free previews, granted I missed the last one in September but before that the last one was in 2016 sometime when they were Time Warner. It seems like the other providers get more free previews.
Also, I wish they sent out mailers or something to let us know there will be a free preview. Most times we're clueless there is a free preview going on. Usually I check the information channel and sometimes it's on there but who checks that channel regularly?