Image vs File

Newbie-type question. I selected full disc backup, which I understand is then an image.  I also have it set to do four weekly incremental backups in between the full backups to save space on my external HDD.

So, then, do I have image backups or are the incrementals just file backups, so I have a hybrid?  Or, is my full disc backup actually just an "all files" backup with four incremental file backups?  I ask because in case of a needed restore, what do I restore?  I do daily file backups with another program, so should I just do a weekly full disc image, but limit how many are kept?

The type of backup chosen dictates what the backup file types will be, so you selected to do a Disk & Partitions backup, all the files created are of the same type.

The Incremental backup files contain just the changes (to disk sectors) identified since the previous backup file created in the same sequence.  Each Incremental backup file is dependent on the backup file before it, as this is what the changed data is based upon.  To recover from an Incremental backup chain, all the files are needed unless choosing a recovery point from an earlier file in the same chain.

When you do a restore / recovery, you just choose the latest Incremental file in the chain (assuming you are recovering back to the latest recovery point), and Acronis will take care of handling the recovery of data from all other files in the chain.

If your current full disk backup also includes all your files that you backup daily with another program, then you already have a comprehensive backup plan that would allow you two different methods of recovering your files.  You can recovery with your other program, plus you could also recover files & folders from your full disk backup if needed.

The decision on how many disk backups you perform using Acronis really depends on how much space you have on your destination backup drive and the size of data captured by the backup task?

Acronis provide an Automatic Cleanup option for your backup tasks on the Backup Scheme options page.  My personal preference is to use: 'Store no more than X recent version chains' which I find is perhaps the easiest to understand.

A 'recent version chain' = 1 x Full backup plus the Incremental backups created before a new full backup is created, so 1 x Full and 4 x Incremental backup files per your post.

Automatic cleanup works only with complete version chains and nothing is deleted until the next chain has been started successfully with a new Full backup file.

What this means in practice is that you always need sufficient space to hold a minimum of 1 full chain plus 1 extra full backup file.  This would equate to using 'Store no more than 1 recent version chains' in the cleanup options.

Steve - a truly impressive and comprehensive answer to my specific situation.  Thanks so much.

So, instead of what I'm doing, is there any benefit in doing a full disc image every week since Acronis 2019 will automatically take the last incremental image and work back to the last full in case of a restore?

I could do the weekly full, but, as you say, I would need to set it to delete images more often, get a bigger HDD or go to the cloud. 

I would caution against creating very long / large incremental file chains as these expose a potential weakness!

As mentioned previously, all files in an incremental backup chain are required.  Acronis provide an option that would allow you to create Incrementals only after the initial full backup, but this would then mean that you cannot afford for a single file to become corrupted, deleted, damaged etc, as this would break the backup chain at that point, rendering all subsequent following files useless for any recovery!

Personally, I tend to stick to the default settings for how many incremental files get created before starting over with a new Full backup, i.e. I use either 5 or 6 incremental files, so my chains are kept to either 6 or 7 files in length, then a new chain started.

The frequency of how often you make a new full disk backup should be determined in part by the degree of change that occurs on your computer.  The Windows OS tends to have lots of small changes taking place constantly with regular Windows Updates, updates to security applications and virus / anti-malware definitions etc.  What you need to consider when deciding on the backup interval is how much work will be involved should you have to recover back in time, which in turn depends on your backup scheme.

The other aspect here is to not put 'all your eggs in one basket', i.e. to make backups to different locations, so that you have multiple options for recovery.  I make 3 different regular backups of my main Windows laptop, with 1 backup kept locally, 1 backup to my Synology NAS and the 3rd backup to the Acronis Cloud. These backups run twice a week to the different locations and use an Incremental backup scheme with 5 or 6 files before a new full is made, thus a new full is being created approximately once a month, and incrementals twice a week.
Note: backups to the Acronis Cloud are different in that a full backup is only uploaded once when the backup is created, after which a Delta comparison of changes is uploaded.

Again, very clear answer.  Thank you, Steve.

Sage advice about keeping the number of increments low - I go for the default or fewer.

While I have some surprising success with a backup using ATI 2014 which is still creating working backups with 100+ increments. However I have a weekly backup with default used and the data is not critical. Moral: The fact that something can work does not mean that it will always work. Abundant caution is always the better approach

Ian