the three bears
Email chess is excellant training for all forms of chess you choose to play.
Blitz chess allows you to familiarize yourself with multiple opening lines, and become comfortable with fast play when necessary, i.e. time trouble. However, it does not improve ones game all by itself.
30 minute or quick chess is good when you are looking for a complete game here or there, but it too leaves you lacking in the end.
It's not so much a preference as possibly a mental work-out plan. How much improvement are you looking for? etc.
Half hour is still too fast for me. I prefer at least an hour for practice games, and preferably 2-3 hours for tournament games.
--Fromper
recently i've begun to compare myself to the baby bear in the three bears tale=papa bear's porridge was too hot, mama bear's was too cold, and baby bear's was just right etc. i am comparing this to email chess=too cold, blitz chess=too hot, and say half hour timed chess game=just right. i realize i am levelling down for this comparison, but feel i am not alone in this assessment. what do all of you think?