So the third draft is on. I've done a re-jig of the text which requires (gulp) a change of tense in great big chunks of the story.
I've always thought writers, like drummers, have a natural rhythm. If you're talking music my natural rhythm is a slightly skewed 5/4. Read into that what you will.
As far as writing is concerned my natural rhythm is first person, present tense.
I may deal with point of view later, but tense is definitely a sticking point for me. Most literature is written in past tense. It works pretty well, the idea that someone is telling you a story that happen some point in the past seems plausible to any audience.
Present tense though shoves the story right in a reader's face. When you read present tense you tend to perceive an urgency to the story. Everything that happens is right here, right now. Maybe that's why I like it. As a reader, you experience it like an observer.
Anyway, i find even when I try to write in past tense, present tense slips out at every opportunity, which makes for an uphill battle to edit.
All of which brings me to the case in point. Early drafts are usually in present tense, so if I decide that the story needs to change it inevitably involves detailed investigation of every sentence with painstaking edits galore.
There is an upside, however. By the third draft, writers have a tendency to skim, rather than read properly, which means editing can be a little less than thorough. Changing tense has a tendency to sharpen your eye though.