Backup files in STAAD are saved as .SBK file type. You can take as many time interval backup as you want. More over you can compare two backup models for changes being made. You can set predefined time intervals at which model can be backed up. By default backups are saved in the folder where model is saved. You can change that too. For opening backup manager, start STAAD and in project task open backup manager. Set no. of auto save backups and time intervals for the same. Set no of manual save backups, keep backups as less as you need. Because, that consumes disk space. If you are a new modeler, you should be saving more backups, but if you are an expert, you might need only 3 to 5 backups, that is too much for the experienced STAAD user. Set backup directory, by default the project directory is the backup directory. You can change the backup directory by un checking the project directory option and specifying the directory path for the backup. One should have