Three important factors to consider:

Bidding position

The extent to which pre-emptive bids obstruct your opponents’ bidding depends both on where you are in the bidding order and which suit you’re bidding.  If you are first to bid, this is a good time to make a pre-emptive bid - neither of your opponents has had a chance to bid yet so you are getting in the way of both of them.  Yes, you are also making things a bit trickier for your partner when they have a good hand, but two opponents to one partner is a ratio in your favour.  When one opponent has passed ahead of you - you are in second seat - you are now only getting in the way of one opponent that might have a good hand. The other one has already shown that they don’t, by passing.  Given that you can also be making things harder when it’s actually your partner that has the good hand, this one-to-one ratio is less attractive.  If you are in third seat - both partner and one opponent have passed, now you know that your partner doesn’t have a good hand and there’s a pretty good chance that your left hand  opponent does, so the case for interference becomes stronger again. What this means in practice is that if you are in second seat, you should only make pre-emptive bids with the better examples of the hand type, using the criteria we outlined in the video to make that judgement.

Vulnerability

Vulnerability is very important when deciding whether to make a pre-emptive bid.  When you are vulnerable and fail to make your contract, you could allow your opponents to pick up a nice penalty score when they were only going to make a smaller part score if you did not interfere. So as with pre-empting in second seat, you should only pre-empt with the better examples of the hand type when you are vulnerable because the risks outweigh the gains. Combining these two factors for consideration, you can see that second seat, vulnerable is the most high-risk situation in which to make a pre-emptive bid and you should only do so with very ‘pure’ hands whereas first seat, non-vulnerable is the very best and you might do so with a much wider range of hands.

One bid only

When you make a pre-emptive bid you are giving your partner a very clear picture of your hand so they are now in the best position to judge whether to bid more.  For this reason you should never make another bid in an auction where you have done this unless partner makes a very specific response (which we will come to soon) that asks you to do so. It can be tempting to go on competing when you have a very long suit but it’s much better to let your well-informed partner decide when to bid on.  Decide before you bid how high you are prepared to go and just make that one bid.