The cost for a shredder, or for paying to have it done will likely be higher at the end of ten years than today. How would buying affect your taxes/depreciation, and do you want to have a shredder? That would be real light use, so I think a good name should hold its value. Are you good with having to wait a while to mow it sometimes, or is it sensitive to time? Would you ever work it for others, or would it only pay you back your investment?
You bring up a good point. I plant a crop and graze 15-20 calves every year. I do this as a side business and file it on my taxes. Last year I bought a 6k wheat drill and a 2k chisel plow. My accountant cautioned me on having my cattle operation classified as a hobby if I kept losing money every year due to buying expensive equipment. For example this year I spent just shy of 20k on calves and hope to make around 3k profit on them.