It really depends on the action and many other factors, such as, will you bust out if you lose, are you near the bubble or a ladder up.
But in most cases, JJ is considered a premium hand and it should always be treated as such, as it will only be dominated by other 3 pairs preflop. It is usually a Raise or Shove kind of hand. But it all depends on the situation.
Fun fact, I once got dealt JJ, flopped Quad J, slow played them as one should, and my opponent rivered his Quad K and knocked me out of the tournament near the money. Worst bad beat of my life, lol.