#1
My Fender Jazz Deluxe has the truss rod at the heel of the neck, like the old vintage models. i can reach it and adjust it without taking the neck off from the body, but i wonder if its necessary to still do so ?
#2
No, and you'd be better off not taking the neck off to adjust. Doing so introduces the potential of stripping out a screw hole in the neck or resetting it slightly crooked and ending up with misaligned strings over your pickups and neck.
"Quick to judge. Quick to anger. Slow to understand. Ignorance and prejudice and fear walk hand-in-hand."
- Rush, "Witch Hunt"
#3
If you can adjust it without taking the neck off, why would you want to take the neck off?
Quote by AlanHB
Just remember that there are no boring scales, just boring players.

Gear

Bach Stradivarius 37G
Charvel So Cal
Fender Dimension Bass
Hartke HyDrive 210c
Ibanez BL70
Laney VC30
Tokai TB48
Yamaha FG720S-12
Yamaha P115
#4
It is acceptable to remove the neck to adjust the truss rod.
What you must not do is over tighten the screws when refitting the neck, also, check the alignment of the neck prior to making the final tightening of the wood screws.
Don't make to big a turn of the truss rod especially when tightening, quarter turn increments are advisable.
G&L L2500
Squier Affinity Jazz Bass 5
Ashdown RPM pre-amp
Ashdown Little Giant 1000
300 watt 15" powered cab
450 watt 15" powered sub bass cab
2x10 + horn
1x15x10 + horn