Chris J.
Yelp
SUNDAY: CLOSED
MONDAY: CLOSED
TUESDAY: CLOSED
Chummy's is technically open for a whole, generous 6 hours and 15 minutes, four days of the week (Wednesdays, Thursdays, Fridays, and Saturdays, from 10:15 to 16:30).
So, if you are a normal human and want to get some coffee on your way to work in the morning.... SORRY, they don't open until 10:15, and then only on 3 of the 5 days of the normal work-week.
Also, you better rush to get there before they closed up shop again, at 16:30, a full half hour before most people who work in an office get to leave.
This week, they were also closed on Wednesday and Thursday. So, you have to ask... Do they even want to be in business?
Also, students and remote workers are not welcome, as the sign clearly says "SORRY NO LAPTOPS TABLETS" which is pretty much at odds with almost every other coffee shop on the planet, and out of touch. Coffee shops where people can work and study become valuable local fixtures with loyal customers, who then promote your store to others. This is lost on short-sighted owners who don't see the value of welcoming people.
I live nearby and I've only caught them open ONCE, and to be honest, the coffee was decent but it's still not worth the risk of spending your time to walk there, and finding them closed (which they usually will be).
Recommend you just head to Borgman & Borgman instead, https://www.yelp.com/biz/borgman-en-borgman-leiden as this place is just a hobby for the owners.
Their business space on Breestrat would be better utilized by another store that is actually interested in doing business.