Garmin eTrex 30

Limits:

2,000 GPX files
2,000 waypoints
5,000 geocaches
200 routes, 250 points per route
200 saved tracks
2,000 archive tracks
10,000 points per track
100 custom map tiles
250 BirdsEye Imagery files
Approximately 3,000 mapping (MapSource/MapInstall) segments

See the Garmin Support FAQ which lists the file limitations of Garmin outdoor devices.

References

http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin

-- Frank Dean - 4 Feb 2016