CRI is a helpful index ranging from 1-100 that refers to how well a light source reveals the true color of the objects being illuminated with 100 being a perfect source of light, such as natural sunlight. The higher the CRI the better the light source where color rendering is important. In the home, high LED CRI of 90+ is especially desirable in bathrooms where cosmetic makeup is applied and skin tones are critiqued.
In kitchens and dining area's high LED CRI of 90+ will make food look more palatable. Lower CRI can be acceptable in garages or security lighting and other areas where exact color is not as critical. Most commercial retail environments prefer very high LED CRI of 90+ in order to present merchandise in the best light. High LED CRI is of course a necessity in art studios and museums when presenting colorful items or images for viewing.
While 90+ LED CRI is becoming quite common in brand name LED bulbs and fixtures, there are still lots of lower cost LED bulbs and fixtures on the market, especially at big box discount stores and online mass retailers like Amazon. The average consumer may be unaware of the importance of selecting a high CRI LED bulb or fixture, mainly because ALL "old school" incandescent and halogen bulbs were at or near 100 on the CRI scale. Therefore this was not a critical factor of comparison when purchasing bulbs in the past. On the other hand, most consumers think of florescent lighting as inferior in quality. One of the main reasons for this accurate impression is that most florescent bulbs (either CFL or tubes) are low on the CRI scale. If you have ever looked at yourself in a mirror under a low quality florescent light you might have noticed that your skin tone looked colorless. That is what low CRI in the 70 range looks like.
Most reputable brands of LEDs will publish the CRI rating on the packaging that the bulb comes in. CRI is not effected by how "warm or cool" the light is. This is another measurement shown in Kelvin degrees. Both warm and cool white light can have either high or low CRI. Polar-Ray.com displays the CRI index rating in the information section of each of its LED products.