Change in the permalinks structure

Hi everybody,

I’ve been posting for 5 months using the following permalinks structure: https://www.lonifasiko.com/2013/02/22/sample-post/

In fact, I admit I have not worried too much on this, but now, trying to optimize a bit my blog, I’m wondering to change to the most simple permalinks option: https://www.lonifasiko.com/sample-post/

Are there any inconveniences or incompatibilities because of having some posts with the old structure and the new ones, with the new structure? I do not foresee any problems and I only see advantages because of having some more space in the URL, but would like to hear your opinion.

What about using categories or tags before the post name, is this useful, makes a significant difference for SEO stuff?

Thanks very much in advance,
Miguel.