Your military maintanence is most likely set to zero if you are not recieving any reinforcements at all.
To check for attrition, select your armies and look at the xx% to the top right of their little data block. If it's anyhting other than a green 0% they are taking attrition and need to split up.
To check for attrition, select your armies and look at the xx% to the top right of their little data block. If it's anyhting other than a green 0% they are taking attrition and need to split up.