I think Craglorn used to be a sub-only area. If you’re referring to Craglorn, it’s open to everyone for free. The later DLCs starting with Wrothgar are accessed through a sub or permanently buying.

With the way the game is set up now, There are a couple of ways to go.

If you sub for a month, it unlocks most dlc zones during that month. (Not Morrowind and Summerset). You can go try the zones and see if you like them. Some are probably worth having permanent access to, while some are smaller zones where you can play through in a couple of days and then just let access expire if you don’t maintain the sub. Hew’s Bane is a good example...I like doing the thieving stuff there, but a player who doesn’t really play sneaking and stealing might not go there beyond the main storyline.

I personally have ended up buying half the DLCs. When I’m subbed I play the ones I don’t own if I keep stuff there, then I buy the ones I like going to frequently.

If you really like the DLCs and plan to sub for a while, the pack that opens four DLCs for 5,500 crowns is a good value. You could buy a 3 or 6 month sub, then save a little money and crowns unlocking DLCs that way. I think buying those four individually is 8,000 crowns.