Good for you for being in the habit of checking your bike before each ride. Tires get old and brittle and have thread separation. Probably depends on ozone and uv exposure and maybe road grime/chemicals. But some rubber compounds have better longevity than other.
Where are the cracks in your rim? Are they where the spoke nipples attach, or on the sidewalls? Sidewalls do wear thin from braking, faster on sandy roads. Cracks near the nipples would indicate excess spoke tension beyond what the rim could bear. Low spoke-count wheels need higher tension and may fail sooner. How old are your wheels? Good your LBS is honoring the warranty.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72