Instead of calling update_some_regular_fields() method at the end of overwritten create() and write() methods, why can't I just decorate update_some_regular_fields() method with @api.onchange() or @api.depends()? This would shorten the code considerably and make it readable, but the decorators seem to only react on changes from UI and ignore all other programmatic changes to DB records.
Also, with self being a virtual record in the onchange method, changes to records other than self are obviously ignored.
Maybe it's more of a feature request?