If you are only doing daylight timelapses, there are quite a few cameras (including non-Canon) to choose from. For example, I have a Pentax W90 that has a timelapse function built in, is waterproof and light enough to fly with a kite and Picavet rig. Image quality is of course nowhere near DSLR but in truth not too shabby. I've strapped it to my motorcycle for several hours of riding, it just keeps on shooting until the battery dies or the card is full. My old Canon G2, although quite long in the tooth, is timelapse capable with a GentLed IR trigger. Only 4MP, but for timelapse movies the individual frames really don't need to be huge. For astro timelapses I use my 60D and modified 40D. I'll consider shutter replacement when it becomes an issue, but until then, I bought these cameras to use them. Like my knees, they won't last forever.