I mostly take shops to keep my monthly expenses as low as possible.
I will gladly take a $10/$10 vitamin store shop, for example, because a) they are in the mall or on base, and I can pick up 2-4 other shops in the same location, at the very least, to make it worthwhile, and 2) that's $10 that's not coming out of my pocket for vitamins. I do three of these a month to cover my vitamins, husband's, and the kids'.
I'll take the dreaded Ross purchase/return shop because I have gift cards there that I keep forgetting to use, so it gets me in the store and looking for treasures. I do the Goodwill shops for the same reason... no giftcards, but... it means I get to donate something that I'm not getting any use out of, and go on a treasure hunt for something I would use.
I do postage shops, bonused or not, because I'm forever mailing shop swag to my sister, nephew, and friends. I'll also use them when I sell things I no longer use on eBay, because it makes my listings more attractive when I can offer free shipping.
For me, balancing shopping with my everyday life has given me ways to lower expenses, streamline my outings, maximize profits/savings.
There is one company that offers low pay for most of their shops, but pay through Paypal and pay quickly, and the reports are minimal, the shops are easy. I do at least 3-5 of their shops a month, and that money gets set aside to buy myself some frivolity, small reward, etc... on eBay.
There is another company that I also perform 4-5 shops a month, they also pay through Paypal and pay quickly... I use that money to "stock up" on things I find on eBay for very cheap. Just last week, I stumbled across a brand new $180 light leather jacket in the last hour of its' listing, and snagged it for $28. I also use this "stock up" money on eBay to buy things like homeschooling materials, dog collars (they wear out about once a year) and many other things. I'd rather buy when the quality items are going for dirt cheap, before I need them, rather than wait until I need them and pay full price.
I guess it is safe to say that we all have our own reasons and methods for the way we choose our shops.
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Plan the work. Work the plan.