I have a better strategy for this. Do not delete anything and keep adding your files instead of replacing or deleting files on the MicroSD. This strategy ensures that you use all the blocks (No wasted free space) instead of oppressing few blocks and thus made them corrupted. Keep adding files till it becomes full then start to do your own replacing and deleting.
Also try replacing and deleting on the computer hard drive, meaning you make an image of the files that are on the MicroSD then do the work on the HD then bring it back to the MicroSD.