system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Is there any logical reason for jedi NOT to carry an extra lightsaber?

We see jedi drop their lightsabers all the time in the movies. For such an important tool that could save their life, why not carry a backup? What Palpatine did was smart, he carried an extra lightsaber, so when he lost his first one to Mace Windu, he still had another to fight Yoda with.
gpt
Well, they don't exactly hand out kyber crystals like candy, so there's an element of expense to a backup saber.  
That's part of it, but the bigger part is that you shouldn't be using your lightsaber all that much anyway, so situations in which you lose a saber and need another should be exceedingly rare in a Jedi's career.  
Rare enough that a backup doesn't make sense.