Buying an ice machine? Size it for your busiest summer day, not an average one.

Start with your own numbers. A common rule of thumb for restaurants is about a pound and a half of ice per guest a day. Bars, drive-thrus and places with seafood displays use more.

Add it up for your busiest day of the year, not an average Tuesday. Then add room on top, because guests drink more in summer and the machine makes less.

Remember the bin. The machine makes ice all day and night. The bin holds what you need for the rush. A bigger bin can cover a peak that a bigger head alone can't.

Every machine lists how many pounds it makes in 24 hours. That number depends on the air and water temperature around it.

Spec sheets usually list output at more than one set of conditions. Look for the number at hot air and warm water. That's closer to what you'll get in July in a busy kitchen.

• Full or half cube: Melts slowly. The standard for soft drinks and cocktails.
• Nugget: Soft and chewable. Popular in drinks and blended beverages, and many guests ask for it.
• Flake: Packs tight and molds around food. Best for seafood, produce and salad bar displays.

Some stores need two machines: cubes for the bar and flakes for the display.

Location decides how hard the machine works for its whole life.

• Air: Keep it away from fryers, ovens and dish machines. An air-cooled machine needs the clearance its manual calls for.
• Water: Plan a filter on the water line from day one. Hard water is the top cause of scale and service calls.
• Drain: It needs an open drain with the right air gap. A machine that can't drain floods the floor.
• Power: Give it its own circuit, sized to the label.

If the only spot is hot, ask about a remote condenser that sits outside or on the roof. It moves the heat out of the kitchen.

Put descaling and sanitizing on the calendar the day the machine goes in. Write down the model and serial number, and keep the manual where the crew can find it. A new machine that starts with a filter and a schedule stays a good machine longer.