I usually do and I haven't had any adverse reactions. As long as they are stored in the fridge you should be OK.
I usually have em cold the next day as a sausage sandwich.
Also, they'll last a good few days after the use by date if in the fridge. Use by dates have only appeared in the last 20 years or so and yet the human race still survives.
A few years back, I cooked a load of sausages as I forgot to put them in the freezer, then once cooled, i froze them and they was fine reheated as long as you defrost them first.
i cook sausages one day, s and then decide against eating them and heat them up the next day, not problems at all.
In fact, i am going to cook some for work this week, and warm them up in the microwave at work and have a sausage bap. cheaper than buying them from food to go.
Why cook a whole pack? Why not cook what you needed for that night and then chucked the rest in the freezer? My freezer's full of meat/sausages/bacon that's been bought from Tesco because it's reduced due to being at the date!