Remember to service your tool ., s LOL

[swampy 6x6]

Hi
Its all about vacuum and how many microns you are are getting down to and how long you are staying there .
2 Areas
tool vacuum leaks and
evacuation setup

LEAKS ===vacuum
Buy a micron gauge
Reseal manifolds with new o rings [use silicon grease OR di-electric grease ] and flush with liquid refrigerant to remove excess grease .
Leaking shaft o rings show under vacuum ,reading fluctuates when knob is turned

Micron test pump by itself
micron test each hose individually
micron test manifold by it self orings and analogue gauges all might leak
Prefer vac test overnight to get the best reading possible

R134 A couplers or similar
new o rings
Nylog wipe onto manual turn knob shaft and threads
test with an alloy hose fitting service valve thats been welded shut

A bad manifold / hoses setup can stop you from getting down to below 3000 microns ,, couplers around 1000 microns
All testing is best done with an empty cylinder . This stabilises the reading

SETUP
If u using charging hoses your micron numbers will more likely to rise
Your setup canbe individual but I find a dedicated vacuum setup works best ie honest micron gauge readings
I personally use R134a coupler with a 1/4 Sae Y adapter for ,,,charge set up and separate evacuation setup