# Option for rescan to check only filesize & date
**URL:** https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074
**Category:** Feature
**Created:** [March 30, 2016, 9:33am UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074 "2016-03-30T09:33:50Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@hakakou](https://forum.syncthing.net/u/hakakou)
#### Post date: [March 30, 2016, 9:33am UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/1 "2016-03-30T09:33:50Z")
As I understand, on each rescan a hash of each file is made. Could there be an option for SyncThing to only evaluate modifications based solely on file date/size? I think this would make rescan time very fast and is more appropriate for my scenario.
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### Author:  [@canton7](https://forum.syncthing.net/u/canton7)
#### Post date: [March 30, 2016, 9:35am UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/2 "2016-03-30T09:35:20Z")
> [@hakakou](#):
>
> As I understand, on each rescan a hash of each file is made
Incorrect.
> [@hakakou](#):
>
> Could there be an option for SyncThing to only evaluate modifications based solely on file date/size?
This is what currently happens.
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### Author:  [@calmh](https://forum.syncthing.net/u/calmh)
#### Post date: [March 30, 2016, 9:43am UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/3 "2016-03-30T09:43:24Z")
… except of course when size or date (or permissions) _do_ differ, in which case we _must_ rehash the file. 🙂
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### Author:  [@hakakou](https://forum.syncthing.net/u/hakakou)
#### Post date: [March 30, 2016, 9:53am UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/4 "2016-03-30T09:53:22Z")
Ok thanks. I misunderstood this.
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### Author:  [@jaystrict](https://forum.syncthing.net/u/jaystrict)
#### Post date: [March 30, 2016, 12:48pm UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/5 "2016-03-30T12:48:25Z")
Just out of curiosity: Why do you have to rehash the file if only the permissions differ?
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### Author:  [@calmh](https://forum.syncthing.net/u/calmh)
#### Post date: [March 30, 2016, 12:52pm UTC](https://forum.syncthing.net/t/option-for-rescan-to-check-only-filesize-date/7074/6 "2016-03-30T12:52:43Z")
We don’t, technically, but we take it as an indication that something happened and do it anyway to make sure.