While frequent oil changes are certainly a good suggestion, you have come to the conclusion that worn seals and guides are due to infrequent oil changes. There are countless other factors. I change my oil even more frequently than you (2,500 - 3,000 miles) and I feel that my engine benefitted from the new seals. It was a fun job to do anyway since I had never done it before.
John, the KD tool sounds like the way to go. I did my seals with the Pep Boys $20 tool and it was a very poor quality tool.
Experience is something you don't get until just after you need it.