How many is too many?

With tomatoes, I sow 4 of each in the hope that one will survive. If they all do, they're all planted.
With old seeds, I sow the packet as I don't expect many to germinate. However, the old leeks and old red cabbage have surprised me and I have about 50 cabbages and hundreds of leeks.
I can never grow too many courgettes or beans. Anything that germinates is planted out.
Most flower seeds are sown in situ and I hope for the best.

Just as every seed deserves a chance, every seedling deserves a life.