I belong to both Costco and BJ's Wholesale Club - here's why it's worth it to pay for both memberships

In my shopping experience, BJ's tends to have superior coupons available on a more regular basis.

Though you need to clip them — they aren't automatically applied to your account — the coupon book is regularly mailed to your home address. Alternatively, you can electronically "clip" the deals you need via the BJ's app.

Some of my most common purchases frequently have coupons available, resulting in an average of $5 to $15 in total savings for each shopping trip. On top of that, BJ's accepts manufacturer's coupons, while Costco does not. This can result in doubling up on major savings for certain items, if you're a savvy shopper and avid coupon collector.

"Wholesale clubs don't traditionally accept manufacturer coupons, but BJ's is the exception, which provides you a great way to save money," Krazy Coupon Lady co-founder Joanie Demer told CNBC.

This may vary based on your location, but in my experience, there's a marked difference in the crowds at each of my local BJ's and Costco.

The Costco I go to is rarely, if ever, empty. Practically from the moment it opens — even on weekdays! — shoppers are lined up and waiting to enter at the doors. On the flip side, my BJ's club is essentially a ghost town during typical weekday business hours.

BJ's also offers a self-checkout lane, which the typical Costco does not. This, obviously, helps speed things up and reduces the overcrowding and massively long lines that Costco near constantly suffers from.

It's virtually impossible to get an accurate read on whether BJ's or Costco has definitively better pricing overall — and people have certainly tried.

Personal finance writer Lauren Greutman looked at 40 different items available at Sam's Club, Costco, and BJ's and concluded that BJ's prices beat out the others' more times than not (by a small margin). However, her analysis found that Costco tied or beat BJ's on certain items (like their pricing on Kraft American cheese slices and dish detergent, which were each significantly cheaper at Costco at the time of publishing).

Similarly, My BJ's Wholesale, an unofficial blog dedicated to the store, ran an in-depth price comparison looking at the store brand pricing for Costco's Kirkland brand and BJ's Berkley Jensen and Wellsley Farm brands. The blogger found that Kirkland was king when it came to some items, like generic vitamins, painkillers, dish soap, batteries, and laundry detergent, while BJ's two brands won out in terms of pricing for things like diapers, toilet paper, and paper towels.

So in the end, it's all about what you are regularly buying — if you're a savvy shopper who enjoys hunting for the best prices and doesn't mind trips to multiple stores to get those bargains, getting certain products from BJ's and others from Costco is a no-brainer.

While the hours of operation aren't standardized across every single store, most BJ's clubs have significantly later closing times than Costco.

My local BJ's Wholesale is open from 9 a.m. to 11 p.m. Monday through Saturday, which I find pretty impressive. On Sundays, it's open from 9 a.m. to 9 p.m.

Costco's availability pales in comparison. The Brooklyn location is only open from 9 a.m. to 8:30 p.m. Monday through Friday, from 9 a.m. to 7 p.m. on Saturday, and from 9 a.m. to 6 p.m. on Sunday.

Even if you generally prefer Costco to BJ's (as I do), it undoubtedly comes in handy to hold a BJ's membership as well, in the off-chance you have a late-night wholesale emergency — which has certainly happened to my family, particularly in the days before major food holidays.

This is perhaps a no-brainer, but it bears stating: Costco and BJ's do not have identical inventory.

Each store negotiates with certain companies and brands to ensure their availability and their rock-bottom pricing. This means that particular items end up being exclusive to a given store. Unfortunately, it also means that certain things can just as quickly disappear if the deal is renegotiated.

If you have a strong sense of brand loyalty, this will appeal to you; if you're less interested in what brand you're purchasing and more keen on getting the cheapest possible version in minimal trips to different stores, this will be less important.

And of course, if you're a Kirkland enthusiast — the brand's generic items, including toilet paper and paper towels, are widely considered to be the best of the best and super cheap — you'll need to maintain a Costco membership just for that. Don't forget that rotisserie chicken either!

If choosing the healthiest organic options for your food and drinks is important to you, Costco has a leg up — currently, the store has the greater selection of organic items.

In 2015, Business Insider reported that Costco was even on track to beat Whole Foods as the country's top seller of organic food. A year later, Costco reportedly did indeed eclipse its rival, achieving over $4 billion in annual sales from its organic products.

BJ's inventory of organic products is still growing, but shoppers with that particular consideration in mind will want to visit Costco over BJ's. At least for the time being.

Costco doesn't have a hard deadline to get a refund for non-electronic items, whereas BJ's does (you need to return the item within a year of receiving it). While we'd never encourage the abuse of Costco's notoriously lax return policy, the fact is that if you're iffy about a product, you should use Costco, not BJ's, to buy it. The likelihood of easily returning it is much higher at Costco.