Some students need lots of help from our service, others just need it occasionally. If you notice a usage limit has been set in your account, it means your provider has decided to set a cap on how much time (or how many documents) you are able to use in a given period. This ensures all students have an equal chance of getting help. You'll see your allocation on the right hand side of your account homepage:
If you would like more minutes to use with our service, we suggest speaking to your institution.