Take care of and clean your Legacy. Why? Voltage under load!
Here's a test I just did. Legacy 350 tube plus kick extension tube. Battery: Effest IMR 18500 v2 1100 mah. Atomizer: IGO-L with a 1.4 ohms coil.
Dirty Legacy, received as is, purchased used via Facebook:
No load: 4.14 v
Under load: 3.68 v (average of 4 hits)
Voltage drop: 0.46 v
Cleaned and polished bass contacts
No load: 4.13 v
Under load: 3.73 v (average of 4 hits)
Voltage drop: 0.40 v
Above plus Noalox on all the tubes threads, on the top and bottom screw threads
No load: 4.12 v
Under load: 3.85 v (average of 4 hits)
Voltage drop: 0.27 v
From a 0.46 to a 0.27 voltage drop in 5 minutes of easy work.