Practice PartnerS with a big 'S' for plural

I see a very common bad habit of beginner salsa leads. When they find a girl who's nice and wont mind practising with them, they'll "hold on" to the girl for the whole night.

There are many issues with this behaviour, .... which I shall not elaborate, but the main problem in context of learning to lead, is that the girl will get to be able to anticipate whatever you are trying and it will not give you a proper feedback of your true 'mastery' of the move anymore!

What I would advocate, is for every learner lead to find at least 5 practice partners.
Whenever the lead learns a new move, he should
1) Practice with one until it's smooth or until 15 minutes have passed (which ever is earlier)
2) Find the next partner, see if it's still smooth, if not, keep trying until it's smooth
3) Go to step 2

Once the move works well with all 5 partners, it's time to try it out on the dance floor with strangers.

Now, why don't we just go practice the moves with strangers?
There are multiple reasons, e.g.
1) When you practice with strangers, you are not sure of their level of following
2) When there is a mistake you can't be sure if it's you or them causing the problem
3) Most strangers wont give you (useful) feedback (because it's generally considered no polite to do so unless one is giving true compliments)

One other thing, how to pick practice partners? (good ones are hard to come by)
1) try to find those of a similar level (so that she wont get bored), e.g. classmates
2) try to find those who are keen to learn and knows how to give good/precise feedback (e.g. cant feel the lead, which part not smooth, where not comfortable, etc.)
3) try to find those who wont have pre-conceived notion of how things should be done and have an open mind. (this is VERY important)
4) try to find one who is an advance level follow. This would be the last one you try the new move on and her feedback would be the key to find any final issues. (e.g. instructor/performer, or just dance with your instructor)

Those are the criteria that I would look for. Really tough to find I dare say :P

It takes many many followers to train a good lead.....