I had a problem freeze spot on my kitchen sink line. At that particular location, its only crawl space.. I don't mean on your knees either. It is so shallow I have to pull myself forward with my elbows while totally laying down flat. I would shimmy in there with a hair dryer and thaw out the pipes. It was an awful place to get to. I got sick of that. So, 6 years ago I ran a heat tape line down the cold line and back on the hot line. I never plugged it in. The plug hangs in an accessible place in my basement. On the -15 degrees night, I got up for work and ran water on both the hot and cold sides, then the wife ran them when she got up about 4 hours later. Everything was fine. Then last night it got down to -1. Since today is my day off, I didn't get up in the middle of the night to run water. This morning, no water on the cold side. I went in the basement and plugged in the heat tape, first time in 6 years. 30 minutes later still no water. I noticed the thermostat part of the heat tape was draped over a warm air duct
... So it thought it was warm. I relocated the thermostat where cold air was oozing into the basement thru the crawl space. 5 minutes later, I hear water running in the kitchen sink. This was the first time I had to use the heat tape. It was nice not to get in that crawl space this time, 6 years later..
If I could go back in time, to that moment I installed that heat tape, I would shake hands with myself cause I'm so pleased right now
Good luck to those with frozen pipes,
do a little preventative maintenance now, so later you won't struggle with it like I had to in the past.