I just look at the high side to make sure it's not too high. It can be a great indicator of an improperly working aux fan, plugged expansion valve, or faulty compressor. But as stated earlier, just try to stay around 30 to 35 on the low side and you'll be OK.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280