Bonnie,
>> I don't think that there's any reason why one can't "mix and match".
Sure, but don't you find that unless there are firm rules, one "guru" or another starts to mix and match according to what makes sense on that particular morning, until one day you realize that the whole project has become a "mix and match"!
But as you say, there is no single correct answer. Perhaps it is better to group "thou shalt not mess with me" baseclasses in a monolithic file to make it less visible/accessible/tempting. ;-) It does mean everything gets included if you use a single baseclass which was one of the downsides of the vcx in VFP.
Regards
j.R
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1