As a young soldier in Cyprus in 1974 I was issued salt tablets, in fact there were bowls of them on the table at every meal. My next tour over there was 1984 and by then you never saw a salt tablet. Serving in Belize, which is a bit warm and humid, salt tablets were nowhere to be seen. I think that by the mid 80s opinions had changed and common sense had prevailed, we get enough salt in our food, and some authorities say we take too much salt, so who to believe?
As an addendum, the latest ration packs issued to forces serving in hot conditions contain packs of isotonic drink powder, lots of them per pack for 24 hrs, and the salt content of the food therein has been much reduced. (If you ever get the chance to try some the cherry drink is great!)
I sweat like crazy on any walk and do not feel the need to take anything other than water but we are all different, take what ever works for you, would be my advice.