PAD doesn't have to be a bad thing. I have a good friend who collects and flips custom pool cues. He has built his own private collection worth over $150K from the profits of those efforts. He's taken the time to know the majority of the cue makers of any consequence. He has sold for many of them based on consignment. He attends the major shows and often has his own booth. Thanks to his tutelage, I have my own modest collection of 7 nice custom cures with a value of over $17,500. I'm confident if I had 3 to 6 months to sell them, I'd recover every penny I've invested plus a modest profit.
My friend's basic rules. Know what you're doing, know the market, know the value. Never, never buy based upon emotion, be completely objective. Look for value, find the bargain. Could be someone needing immediate cash and willing to take a loss to get cash. Look to purchase from up and comers whose product are most likely to appreciate as they become more established. Stay away from makers who are throwing out higher volumes at lower prices just to make a living. They'll rarely be able to rise above all the low priced product they've put out on the market. The majority of the higher priced cue makers don't do it for the money. They're already financially stable and do it more as a hobby than a source of income. Those who are also financially well of can afford the nicer equipment. Finally, if you're looking at it as an investment, don't buy factory made products, those almost always go down in price. Factory made products are also sold through distributors who have their markup on the product.
It may take some of the fun out of it but I think these are reasonable rules for pipe collecting as well. The flip side is to just say screw it, buy what you can afford and have fun. Interestingly enough, I think Harris has actually managed, for the most part, to do both. He can easily afford his PAD but he's a smart guy as well and bought wisely.