Dale Davies said

I worked for a company years ago that built a new heavy equipement shop. There was a ddouble entry door so cold air did not get in when you came in or went out. They put a large compressor on the top of the vestibule area with a loop in the piping about 4' up to trap water so it did not get into the air lines. The pipe was 2" to accomodate a bunch of us using impact wrenches. After a while I noticed that the compressor cut in quickly after starting to use an impact. I mmemmentioned this to the boss a few times and that I was sure the compressor tank was filling with condensed water. His reply each time was that there was no water as the loop caught it.
Friday of a long weekend I climbed up and opened the compressor drain. Tuesday morning we came in and all the drywall from the ceiling was in a soggy heap on the floor. Of course I got called into the office and asked about that. I just replied that he said there was no water. First job that day for me was to plumb a drain line down to easy elbow level so the tank could be drained every Friday.
For home use, depends on how much you use the compressor. Every Friday or Sunday night should work fine as it would be the end of the week for working in the garage. Make the drain easily accessable.
A loop does prevent the water getting into your air lines.

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justinp61 said

Mine gets drained for five seconds every forty five minutes via an automatic drain valve. From the valve there is a piece of 1/4” copper tube ran through the wall to the outside.

Unless you change the oil in the compressor often I wouldn’t put it outside. My brother put his outside under a shed, the condensation in the oil would freeze and lock the compressor up. He moved it inside after the first winter.

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