It was what I was told in Home Economics, and it was the rule my mother followed. If you want an official breakdown, here is one from Clemson University
“Refrigerator Storage
The following foods will keep only 1 to 2 days in the refrigerator:
* fresh (raw) ground meats and stew meats
* gravy and meat broth
* fresh poultry and fresh fish
* shrimp, scallops, crayfish, squid
* shucked clams, mussels and oysters
These foods will keep 3 to 4 days in the refrigerator:
* fully cooked ham slices
* cooked meat and meat casseroles
* cooked chicken and chicken casseroles
* pizza
* cooked fish and cooked shellfish
The following will keep 3 to 5 days in the refrigerator:
* opened packages of luncheon meats or deli-meats
* fully cooked ham portions
* fresh meat steaks, chops and roasts
The following foods have longer refrigerator storage times as indicated:
* fresh eggs in shell—3 to 5 weeks
* hard-cooked eggs—1 week
* commercial mayonnaise after opening – 2 months
* hard cheese (such as cheddar, Swiss), opened—3 to 4 weeks
* soft cheese (such as brie, feta), cottage cheese, ricotta, milk—1 week
* yogurt—7 to 14 days.”
I have found that around day 6 the smell test is the most important measurement.