1. There is limited time for many of them
For most deferments/forbearances (such as a General Forbearance) you have a maximum of 3 years and depending on the age of your loan, less. There are some deferments such as the In School Deferment that have no time limit.
2. There are requirements to meet for these
For almost all forbearances and deferments there are things such as proof of income, benefits, etc. that are needed to qualify. The only one that has practically no requirements is that of the General Forbearance.
3. If its based on income, its gross not net;
For the Student Loan Debt Burden Forbearance (always) and Economic Hardship Deferment, (sometimes), these are based on Income. When a deferment, forbearance, or payment plan is based on income it is your gross not net and these are not offset by things such as personalized expenses.
4. Don’t be fooled by the Titles (they are more broad than you think)
If you are unemployed, you don’t necessarily qualify for the Unemployment Deferment while at the same time if you are not unemployed you may still qualify. It is all about the requirements for each deferment or forbearance (in case you were wondering for the Unemployment Deferment the definition is someone who works less than 30 hours a week and is receiving Unemployment Benefits or registered with an employment agency)