Multiple SaveChanges calls in entity framework

I am building my own custom repository, based on entity framework, and I'm creating some extension methods that allow me to save partial view models as entity models so I'm building my own Add and Update methods.

Currently, each method has SaveChanges() from DbContext called at the end which means for every model, one call will be invoked.

I'm building this base DAL pattern for MVC4 sites which means most of the time I will access 1 model, but it does not have to be the case though.

Is it too bad practice to call SaveChanges() for each model when updating i.e. 3 entities or should I add everything first to object context and than do SaveChanges() as some sort of transaction commit?

I know it's kind of late answer but i found it useful to share.

Now in EF6 it's easier to achieve this by using dbContext.Database.BeginTransaction()

like this :

using (var context = new BloggingContext())
{
    using (var dbContextTransaction = context.Database.BeginTransaction())
    {
        try
        {
            // do your changes
            context.SaveChanges();

            // do another changes
            context.SaveChanges();

            dbContextTransaction.Commit();
        }
        catch (Exception ex)
        {
            //Log, handle or absorbe I don't care ^_^
        }
    }
}

for more information look at this

again it's in EF6 Onwards