Q.Why Are the New Leaves on My Tomatoes Curling and Hard?
The new leaves on all my tomatoes are curled up and almost leathery to the touch. After they get more age, they look normal. The little fruit I have now doesn’t seem to be affected, as of yet anyway. What can we do aside from destorying the plants? There are four, what, if anything, can be done in the future to prevent this from happening again?

Certified GKH Gardening Expert
Leathery, curling leaves are normally caused by weather stress. If you have had extreme weather or weather fluctuations, this is very likely the cause and is not an issue.
It could also be a virus, but as you are seeing healthy fruit, then this is doubtful. This article has more information on leaf curl virus:
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-curling.htm