I find plants newly planted out from greenhouse are more susceptible, I think due to softer growth from the tomato fertiliser I give to the greenhouse plants. If I give plants to be planted out a period sitting on a bench outside surrounded by slug pellets, so they're not getting fed and are developing "harder" growth, they're more likely to survive.

While I haven't done systematic experiments, there is a clear difference in slug damage between lush well fed plants, and tighter, apparently less vigorous plants.