throwing frequency?

I recommend twice aweek if you're single and have the time.  If you are married and have a family, once is enough.  Your family comes first.  Plus you'll be sore and no one wants a sourpuss around who is sore and grumby.  I  also recommend three events only.  No more than 12 to 15 throws in any one event.  Be specific with what it is you are working on.  If foot work is the concern then don't be at all concerned about what the distance is.  No markers on the field.  Just footwork.  Get the idea.  If you concern yourself with distance you are simply having a contest with yourself and exercising.  Practice is practice.  You don't even have to throw a weight to get in footwork, which means you can shadow throw all day as long as you strive for perfection.  You need to train the system to recongize a new sensation, new nerve impluses, new positions, etc. This early in the season you can work on rythym with the hammers by simply spining them around.  This is get the shoulders and grip ready for spring and actually throwing.  Again.  Pick out a specific action you want to work on.  In the hammers the best thing is to train yourself to keep your arms long and loose.  In fact I think the hammer is one event in which you need to be extremely relaxed or loose with when practicing or competing.  And never ever toss a stuupud sheaf.  Stay away from it.  Absolutely nothing good ever came from a sheaf bag.  It is in the bible, "Thou shalt not sheaf."