This is really a question of what level of customer service does a consumer expect from a manufacturer and what level are they willing to provide. Customer service builds brand loyalty and in turn brand equity.

As a guy who works in Marketing I'd favor a limited lifetime warranty. Certain things in the first year would be free of charge followed by a tiered replacement fee schedule. As time goes by the fee would increase.

You can't always expect a manufacturer or marketer of products to keep around parts for a 5+ year old product. For more expensive items like something with a motor or electronics that use industry standard or common parts it makes sense that you should be easily able to track down replacements. But, for an item like a fishing rod it is just not practical.

Also, the manufacturer shouldn't be expected to pony up a brand new rod just because they don't have a replacement tip for your 4 year old rod, but the premium price you paid should entitle you to discounted replacement or repair. Part of that higher price tag should consist of warranty claims.

Less expensive rods would only be covered by the one year full warranty, and one year limited after that. Maybe even a one year limited.

Another option, one that most people don't like, is an extended warranty that you purchase up front like Best Buy offers. In the electronics world these aren't a good purchase for the consumer. In the fishing rod world they might be.

Remember that retail prices are usually 5x the materials cost, so it would be pretty easy for a rod company to offer replacement and not lose their shorts since they are selling replacement parts direct to the consumer and avoiding the markups by distributors or retailers.