I just read Scotch's CountingOuts article on NL 5c draw hi. He prescribes never drawing 2 with trips because it makes the hand too face up. But what I've heard is that sometimes with a single pair you should draw 2 which has the following benefits:
- Balances the range for when you draw 2 with trips, allowing you to get more value with trips and increasing your chances of improving with trips
- Allows you to turn a 1 pair unimproved hand into a bluff by representing trips (particularly relevant in later positions when you're opening a hand as bad as 99 and could be getting defended predraw by a better single pair hand)
- Assuming you do this play when the extra card you keep is a high kicker, increases your chance of making a winning 2 pair when you do make 2 pair.
The main downside is it decreases your chances of making 2 pair or trips from your single pair. What do people think?

Well with most poker decisions there are trade offs and adv/disadv to doing something. Keeping the perceived range wider to two pair, trips, or draws seems better in most circumstances

That said maybe there are circumstances and opponents where mixing it up may be best.

If I did say never perhaps that is too strong of a word to use.