Just my opinion, but:
1. You lose a lot of the utility of an aircraft if you are not able to fly it at night or in IMC.
2. Not everyone can afford multi-engine aircraft shares or rental.
3. I've never had too many torches when flying at night, but have several times had too few.
4. Always have your night flying gear with you. The night flight is often as a result of unexpected delays or failures.
5. Complete engine failure is very rare. Thats why single engine aircraft are so popular and practical.
6. Make a mental plan of what actions to take in the event of an airborne problem before you leave the ground.
7. After 1700h in the UK fuel can be hard to obtain.
8. Use "What if?" checks to test your plan. e.g. What if there is a power cut at destination airfield so the lights don't work? An alternate 5 miles away might also be in darkness!
9. Finally, never take anything out of your flight bag and put it down on the ground in the dark. If you're like me it will take you ages to find it again.