I'm not 100% sure, but it sounds like you might be trying to use Stack Overflow as a forum by using the revision history as a conversation thread.
I did look at the revision history for one of your posts, the one you reference in your question about triggers, and I may be mistaken, but it appears as if you're completely removing your initial code examples and questions from your first revisions and replacing them with each edit you make.
In other words, it looks like you're perhaps receiving follow up comments asking for more clarification, or perhaps those users are providing you with troubleshooting steps, and then you're perhaps following up by replacing your original questions with completely separate blocks of code and information, so that the final revision shows only the last step in your troubleshooting process.
On one hand, I think you're making great attempts at making your questions better. Most, if not all of them, are upvoted, and most of them have good, detailed answers, which is oftentimes one of the signs of a good question.
However, my concern is that some information is missing from the later revisions, contextual information that may be important for future visitors coming from Google.
Revision history is generally used to keep track of a question as it's improved, not to keep track of the troubleshooting steps taken on that question. This is likely to confuse most people, and I'm not 100% sure if your questions will have value to future visitors in this format, since many people coming from Google don't necessarily have Stack Overflow accounts or understand how to see a posts' revision history. Also, I'm not sure if the earlier revisions have an impact on the posts' SEO.
You sort of have the right idea: Edit and improve! But my suggestion, to really make your questions useful by future visitors (and more likely to be upvoted), is to leave the information from your first revision intact in your final revision, unless of course the comments indicate that there is too much information that makes the question confusing.
To help improve questions where there are oftentimes some minor discussion involved to get from point A to point B, many users will use a horizontal break to divide one edit from another.
EDIT: Like this!
Lastly, keep in mind that broad questions are less beneficial to the community than targeted questions, so if you do ask a question that gets an answer, and that leads you down the path to a different but related problem later on, then a separate, new question may be best, as long as it's not a duplicate of the previous one.
The fact that you edit your questions to improve them is promising. But be sure that the final product, your contribution to Stack Exchange, is something that a future visitor can read and say "I have that same problem!" and then benefit from the answers. Good luck!