One particular knotty routine for me was a small synth, I knew I had neither the math ability or c wizardry to develop complex things easily so I made sure there was plenty of scaffolding to assist me. For each 1k of audio output, there is easily 1m of debugging output that I would then "query" with perl, pagenate each step that I could page through, etc, debugging was put in from the start.
Allowing flexible debugging strategies that I could adjust for the difficulties at hand just seems right for me and I find often that different programming constructs need different debugging strategies, and I just don't think debuggers are agile enough to let me adjust.
Its really that I'm just too dumb to get benefits from debuggers, although I'm guessing they may be just perfect for folks smarter than me.