In my application I'm currently using forms which allow to enter Title and Slug fields. Now I've been struggling with the slugs thing for a while because I can never decide once and for all how to handle them.

1) Make Title and Slug indenpendent

Should I allow users to enter both Title and Slug separetely? This is what I had first. I also had an option that if user did not enter the Slug it was derived from the Title. If both were enter, the Slug field took precedence.

2) Derive Slug from Title, when content is inserted that's it for the Slug, no more changes

Then, I switched to only Title field and derive Slug from title. While doing it I found out that now I have to change all the forms that allowed user to enter a slug. This way of doing it also prevents users to change Slugs - they can change the Title but it has no effect on the Slug. You can think of it like Slug is uniqued ID.

3) Now I'm thinking again of allowing users to change slug

Though I don't think it is all that useful. How many times does the content that someone already added, spent time on writing it, even require a change of either Title or slug? I don't think it is that many times.

The biggest problem with the 3rd option is that If I use Slugs as IDs, I need to update the reference all over the place when Slug changes. Or maintain a table that would contain somekind of Slug history.

What are you thoughts on these, I hope, valid questions?