Space is an important element to be considered. A DBA has to keep track of space in all aspects and it is good practice to keep an eye on all trends that your DB is going on in case of space. Here are some use full T-SQL commands that will help you in space analysis and tracking.
This DBCC command will show use full information regarding to data file of current database.
This command will provide use full information about total size, used size, unused size, index size and data size of current database.
This use full command will provide you size information of all databases. The size shown is combined size of data and log files.
This use full DBCC command will give you a very detailed view of disk allocation for current database. You will find every information here about storage allocation.