Going grocery shopping is an (at least) weekly chore for most of us, and I find every part of it taxing. Figuring out what you need. Wondering what you might want to eat in the next week. Wandering around the store with a hand-scrawled list that keeps you bouncing around from one side of the store to another. Finally checking out with twice the stuff you intended, most of it junk food.

Over the past few months, I’ve figured out a great way to do grocery lists that has none of those problems. I got a week’s worth of groceries this morning in 25 minutes flat, and it was a total breeze. It uses my company’s free list manager, Trello, but you can get a lot of value out of just having a smartphone with a camera.

Since originally publishing this, I’ve been made aware that there are plenty of shopping list apps out there. I’m sure they’re great and full-featured. But if the best camera is the one already in your pocket, the best grocery list app is the one already installed on my wife’s iPhone. And, for us, that’s Trello.

Phase 1: Keeping your grocery lists

This part is pretty easy and doable by anyone with a smartphone. Basically, every time you make a grocery list, take a picture of it with your smartphone. Then, next time you’re making a grocery list, refer to the grocery list pictures on your smartphone. Seems pretty reasonable, right?

I’ve been doing this for a few months and what I find is that I no longer have to wrack my brain for a list of what we need. It’s very likely that the stuff we just bought recently—and that we don’t have in the fridge anymore—is the stuff we need.

After I’ve made a list, I take a picture, and hand the list to my wife. She works from the paper, and I work from the image on my phone. I even got to the point where I was dividing up the list based on stuff in the produce aisle, which she does, and stuff in the rest of the store, which I do.

After you do this for a while, you’ll build up a history, and you’ll start to see the things you need regularly. When you sit down to make a shopping list, just scroll through your photos for tips on what you might want to add to that list.

Phase 2: Make a Trello Master Shopping List

Once you have a few shopping lists, just open a text editor and type in anything that shows up twice.

Now, go into Trello and create a new card called “Master Shopping List”.

Then click on the card to open it, and add a checklist. You can just keep it called “Checklist” for now.

Now, go back to your text file, copy your text list and paste it into the first checklist item, then click Add.

Trello automatically makes a checklist item for each line. Magic! Now you have something that looks like this:

Note: You can drag and drop the items in the checklist to your heart’s content to order them in a sane way. More on that below.

Phase 3: Shop it like it’s hot!

So, now you have a list that contains most things you buy on a regular basis. Of course, you’re not going to buy everything on that list every time you go to the store. Start by copying the master list into a new card.

Once you have the new card, you can go through your pantry and fridge and just check off anything you already have.

Now you have a shopping list for Thursday’s trip to the store. Go to the store and, using your smartphone and the Trello mobile app, check off the items as you pick them up. When you’re done, move the card to the Done list for safekeeping (more on that below).

Next time you’re making a shopping trip, make a new copy of the Master card and go from there.

Optional Phase 3: Divide and conquer

So this is totally optional, but it helps to divide the Master list up into sections, especially if you’re going to have someone helping you shop. And it certainly helps with staying on task and organized.

On your Master card, create new checklists named, say Produce or Meat and drag the relevant items into those lists. This helps you group items to where you find them in the store. If you’re crazy like me, you can also drag the checklists themselves to mirror your path around the store (e.g., Produce, then Dairy, then Bulk/Nuts, etc).

It helps you stick to your list, as well, saving you temptation, time, and money.

Now, when you’re in the store, you can use those vaunted Trello mobile apps, available for free in both Android and iOS flavors, to guide you through.

Bonus Phase: Refining your Master list

The only caveat here is that if you add something to your Thursday shopping list, it doesn’t get added to the Master list. You can create a new, empty checklist on the Master card called Extra Items. Because of a quirk in the way Trello copies cards, you’ll have to add a placeholder item to the Extra Items list. Otherwise, that checklist won’t copy over.

Now, you can periodically go through your old shopping lists in the Done list and see if there’s anything that gets added regularly. Add that to the Master card and it’ll be there next time.