I carry a water bottle on me at all times - my 2 favorites couldn't look and feel more different

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• Whether I'm traveling a new country or simply running errands, I carry a water bottle on me at all times.
• Since I like to stay hydrated, my favorite reusable water bottle is the stainless steel, 40 oz. Takeya Originals Water Bottle ($30), which features double-walled insulation, two mouth types, and an ergonomic handle.
• If not the Takeya bottle, you'll find the 16 oz. bkr Water Bottle ($38) in my bag. This silicone-covered glass bottle is more suitable for casual use and when it's just not practical to lug around a large bottle.

As someone who likes to stay hydrated and is always drinking water, I count the reusable water bottle as one of my most prized possessions. Rarely will I ever leave the house without one in tow - who knows where my next source of water will be? I certainly won't be waiting until my throat feels parched and my head hurts to seek it out, and I blanch at the thought of buying a wasteful plastic water bottle.

If anyone ever tried to assume my identity, they'd be remiss not to include the 40 oz. Takeya Originals Water Bottle ($30) in their Connie Chen Starter Pack. This is the main bottle I carry around for the gym, travels, and everyday life, and thanks to its size (or maybe the assortment of stickers plastered all over it) you can spot me doing so from a mile away.

You'd think my second-in-command bottle would be around the same size and construction, but it's not. If I'm not carrying my Takeya bottle, I actually like the 16 oz. bkr Water Bottle ($38). While it's much smaller and made from different materials, it has its own merits as a reusable water bottle. Below, I explain why I have both in my rotation, and why you should, too.

The 40 oz. Takeya Originals Water Bottle is an all-around stainless steel heavyweight that will keep you hydrated through the whole day.

The Takeya Originals is the classic reusable water bottle most people think of: made from stainless steel, double-wall insulated to keep cold drinks cold and hot drinks hot, and rugged enough to withstand bumps and scratches.

I like Takeya's design specifically because it has a wide mouth to make refilling, adding ice, and cleaning easy, as well as a small spout lid that allows for precise drinking with minimal spillage.

This patented lid features a leak-proof twist cap that has never failed me and makes me feel confident throwing my bottle into my bag at any angle. When I want to enjoy my beverage (usually water), I can use the small spout and I don't have to worry about water splashing onto my face. This is especially useful when I want a sip of water mid-run or workout but don't want to slow my momentum.

You can hold the bottle comfortably in one hand or by the wide loop handle that lets you swing it back and forth. You can also clip this handle to a carabiner on your backpack. Despite accidental crashes as a result of careless swinging, the handle has stayed resilient and secure.

Impressive insulation capabilities are another reason to consider the bottle.

As Insider Picks reporter Mara details in her review of the Actives version of the bottle, you can fill it with water and ice cubes, and you'll still find intact ice cubes inside 24 hours later. The bottle is frighteningly good at keeping your beverage at your desired temperature, whether you prefer it hot or cold. Almost as importantly, the bottle exterior stays cool and dry regardless of its contents.

Read more: I found ice cubes in this $25 stainless steel water bottle 24 hours after filling it

To some (e.g. all my friends and family who regularly point this out), the 40 oz. size can seem excessive and heavy. But as someone who truly loves drinking water, the size is perfect and ensures I have something to sip throughout the entire day.

It's my savior during long, dehydrating flights, where I typically down the small complimentary cups of water in one gulp; days spent in the city running errands and hanging out with friends; and draining workout classes. Having the large bottle by my bedside encourages me to drink a lot of water in the morning when I wake up, which, among other benefits, increases alertness and jump-starts metabolism.

Because the bottle keeps me constantly hydrated and healthy, I rarely mind its size and weight.

Read more: The best water bottles you can buy

My next most-used bottle, the 16 oz. bkr Water Bottle is quite different: 40% the size of the Takeya and made from glass, but these features also have their place.

This small bottle, compared to the intimidating and utilitarian Takeya, is approachable and stylish - as stylish as a water bottle can get, anyway. It's wrapped in a silicone sleeve that's available in a variety of colors and the shape is far more suited to small handbags and totes than travel backpacks.

As defensive as I get whenever a friend teases me for how large my Takeya bottle is, there are moments when I relent and admit that it simply doesn't make sense to bring it with me.

During trips to my neighborhood grocery store, for example, I would appreciate a few sips of water as I browse the aisles and schlep my bags home, but a whole 40 oz. worth of sips is just unnecessary and will only weigh me down. Other times, the house rules of specific venues or institutions prevent me from bringing in such a large vessel. The bkr bottle is small enough to bypass these rules but still provides enough water for events that are a few hours long.

The size is also preferable for beverages that aren't water. If I make a smoothie, juice, or iced tea at home, I don't need or want a huge bottle of it to go. The bkr bottle is the better option for transporting these sweet, refreshing drinks.

While its glass construction means it's not very insulating, it is durable and shatter-proof, a characteristic further bolstered by the protective silicone sleeve.

In addition, the cap also seals tightly and is leak-proof. Like the Takeya, it has a handle attached to the cap, though it's smaller - for looping a couple fingers rather than your whole hand - and can't swing back and forth.

When I first received the bkr water bottle in an event goodie bag, I thought it was more for looks than function. The pretty bottle has surprised me with its usefulness, and in the right situation, is a strong alternative to my usual Takeya bottle.

The bottom line: If you have $30 to $40 to spend, which water bottle should you buy?

The clichéd but truthful answer is, it depends. For a classic reusable water bottle you can take most places, I love my 40 oz. Takeya Originals for its powerful insulation, drinker-friendly design, and versatile use functions. For a more eye-catching, glass style that stashes in small bags and provides casual hydration, I love my 16 oz. bkr Water Bottle.

At any given time or place, you'll find me drinking water out of either of these great water bottle options.

Shop the 40 oz. Takeya Originals Water Bottle, from $30, here:

Buy it at Amazon Buy it at Target

Shop the 16 oz. bkr Water Bottle, from $38, here:

Buy it at Amazon Buy it at Sephora Buy it at Nordstrom