Semaphore Sam, flying is meant to be simple. There are many good rules of thumb for cross checking safety, but they should not take precedence over the basic rules for safe flying. This means that you must have a good understanding of approach procedures and that they must followed as published. Your rule of thumb may be adequate for most procedures, but somewhere, someday, there will be an exception. If you do not turn at the stipulated position on the chart then you may not have the advertised obstacle clearance; then what rule of thumb do you have for that?
OzExpat, thanks for the comment, but the accolade for this work resides with Mr Olle Akerlind, a retired SAS ground school instructor who wrote “From Take Off to Landing”, and also to Honeywell Safety Systems who republished the document 3-4 years ago as a CFIT ALAR safety initiative.