MSSQL backup

I have two questions related to the MSSQL ability to auto-backup databases.

1. I've setup plans to auto-backup everyday, this is fine, however it makes a backup everyday and I have to go around and manually delete the very old backups, can MSSQL backup and keep only the last 6/7 backups and to a rotation, replacing the old ones by new ones?

2. I'm not backing up the transaction logs, only the database file, will this be enough to restore a database if I want to change to another MSSQL server, or even restore on the current server if something happens? Or, do I also need to backup the transaction log file for that?

Thanks.