Neil Parikh and Luke Sherwin have shared an entrepreneurial journey since the beginning.

They're two of the five co-founders of Casper, the online mattress retailer that launched in 2014 and broke $200 million in sales last year. Prior to that, they co-founded an e-commerce startup called Consigned. And before that, they were friends at Brown University.

That said, it's not surprising that they've developed similar productivity habits--and face similar productivity challenges. Here are the tips and tricks that have helped Parikh, 29, and Sherwin, 28--Casper's chief operating officer and chief creative officer, respectively--optimize their time and fight obstacles along the way.

1. Find the perfect morning routine.

Sherwin's version of a "perfect day" involves waking up, making his fiancee coffee, taking a 20-minute bike ride around Brooklyn's Prospect Park, showering, and then heading to the office. On the way, he'll either eat breakfast or catch up on email, the latter of which is also how he closes the day.

Parikh's morning routine is similar: Work out, eat breakfast (a healthy one, rather than "eating anything"), meditate, and arrive in the office by 9 A.M. "I'm much more focused and attentive and present when I wind up to the day," he explains.

2. Live by your rules of sleep.

Interestingly, neither Sherwin nor Parikh has a nightly routine, save that both men preach the importance of sleep--hardly surprising given the nature of their company. Parikh builds his entire daily schedule around sleep: If he has an 8 A.M. meeting the next day, he'll subtract nine hours--eight for sleeping and one for getting ready in the morning--to determine an 11 P.M. bedtime.

Sherwin says he won't view screens for a full hour before he hits the sack. It helps him get his eight hours, including time spent hitting the snooze button--something he does despite knowing it's "against the rules."

3. Create work-life balance (sort of...).

Both endorse having a life outside the office--even though they sometimes work outside the office.

Parikh often schedules breakfast and dinner meetings. Sherwin says he starts on Casper-related projects around 8 A.M. on weekdays, but doesn't actually get to the office until 8:40. He leaves the office around 7 P.M., but doesn't stop working until 7:30. Occasionally, he'll tackle longer projects on weekends at home, when he has more time to ruminate on them. It's due, he explains, to a guilt he feels when he's not working--a holdover from Casper's early days when all five co-founders were workaholics.

Parikh describes those days as brutal: 80 to 100 hours per week, not exercising, not eating healthily. "Year Two, I would have said, Casper, Casper, Casper," Sherwin agrees. "Now, it's like, bicycle, coffee, Casper, Casper, read, eat, sleep."

4. Maintain health for the mind and body.

Their "health" habits, of course, aren't identical.

Sherwin preaches hydration--"I consume really nice sparkling water at Casper," he laughs--and has recently been using it as an excuse to cut down on coffee.

Parikh keeps a journal and started learning transcendental meditation earlier this year, a practice he calls "super helpful" for focus and productivity. He meditates every morning and tries to meditate in the afternoons for a late-day boost.

They also disagree on one key point: smartphones. Parikh says he's trying to disengage more from his phone, while Sherwin says it's the tool that most enables him to be more productive.

They agree, however, on one of the most important factors to their productivity: consistency. Sherwin ascribes efficiency to repetition--the more you practice something, the better at it you get. Parikh calls consistency the biggest obstacle to his productivity, simply because it's so difficult to achieve. "The more consistent I am, the more productive I am," he says. "I'm trying to develop a habit so it's more natural."