Income tax was originally a temporary taxation. Speed limits on motorways were originally temporary so I would be wary of SMALLDATETIME. Admittedly we will all be dead by the time it becomes a problem but hey, youth loves a challenge so we will bequeath something positive for our great grand children.

I know that SmallInt/TinyInt save me storage space but I read somewhere that Windows only looks at 32 bit integers anyway and so everything gets converted to Int by default. This might be an obsolete observation.

The other thing to remember is that the word NEVER was invented so that God could have a laugh. There are currently 100 or so counties in the UK but if the "European Project" is successfully rammed down our throats who is to say that systems that track UK counties don't end up tracking more than 255 EU equivalents.

That said the intent of optimising your datatypes is best practice but you always need to consider the bloody-mindedness of people using the system