"The boat won't sink" is the type of belief that causes people to die. Catastrophes happen. "Unsinkable" boats do sink. You hit a
shipping container that rips a hole the entire length of one
hull. A fast mono hits you broadside. The boat breaks up on a reef. I agree with Greenwave, if you have a raft it would be be silly to get rid of it. If you have any
service history of the raft, you might be able to estimate what the next
service is. Sometimes it is just replacing expired
food, inspecting, and repacking. You could probably safely skip that, just know that the food/water will be bad. Other services will include pressure testing, testing the CO2 cylinder etc. Those are more expensive, and you probably shouldn't skip those. (Just MHO, if you want to be sure, don't skip any service)
A 42 ft. cat is a lot of boat. On a
small boat, say 30' or less, there is actually a good argument against a life raft. Someone on a
small boat almost always has a small
budget. And storage is much less, and even without a raft usually a real problem. So, in order to have a life raft, you must give something else up. Maybe the choice is between replacing below the waterline hoses or a life raft. Maybe it is replacing 20 year old
rigging. Maybe the liferaft storage is giving up a bigger first aid kit, another fire extinguisher,
emergency repair supplies or
food. Balancing the odds, it is better to spend
money and storage on keeping the boat in good order and crew safe than on a raft.
On a 42' cat, none of those apply to you. I also disagree with using a
dinghy as a liferaft. Catastrophes happen in bad weather/seas.