Pretty much any modern device will have ample storage, but it would still be recommended to have at least 16GB of free space available on your device.
Below are the overall guidelines for if you were to pursue collecting your entire road network and what capabilities are recommended for larger collection efforts.
Devices that only have internal storage, non-expandable memory, will work for data collection.
Just keep in mind that a device with less than 128GB of memory will limit the amount you can collect for a given day.
When you are recording with the RoadSense application it will show you how much free space you have on your device and an estimate of how much that means in minutes of recordability.
To ensure the best result in Data Collection, it is best to record with a MicroSD card for devices that have expandable internal memory, that has a capacity no less than 128 GB of storage.
Here is an example of what they look like:
We strongly recommend using cards of at least this size, as a typical day of data collection, 6-8 hours, could use upwards of 50 GB.
With this in mind, a 128 GB MicroSD card is large enough to hold approximately 2 days of collected data.
When you are recording with the RoadSense Application it will denote, in the bottom left, the available space/time remaining.
Space on the card/device will free up after uploading the data.
This is a LINK to an article from Samsung that shows you how to correctly insert a MicroSD card into the Samsung S9 device: https://www.samsung.com/ca/support/mobile-devices/how-do-i-insert-microsd-card-into-galaxy-s9-or-remove-it/