I would strongly advise against purchasing cues as an investment to hold for a period you are talking about. Under the best conditions you'd be hard pressed to get a decent return on your money. The best cue investment you can make today involves no upfront costs. Call South West Cues in Las Vegas and get your name on the list for 2 cues. In about 13 years, give or take, your order will be ready to go in production. At that point 50% is required. Unless the market for South West cues totally collapses, you're a cinch make a few thousand dollars profit. I could kick myself in the ass for not ordering year after year. I ordered in 2005 and my cues are now being built. South West cues has been quietly subsidizing pool players for a few decades! For the vast majority it will be their biggest pool related score ever.
This is the ONE possible investment you might make. I thought of it right away but decided against suggesting it, not knowing how old you are. For me, that means I would be about my early 80s, so not for me.