To be sure you are earning rewards make sure that it has a lockTime field set.
1. search the transaction using http://kmd.explorer.supernet.org/ .
2. search the transaction ID in the explorer and in the first section at the bottom will be lockTime.
3. check if it has lock time setup. (if it doesn't then it means you are not earning any rewards).
4. if yes, then the address where the tx was sent to is acquiring interest.
Note! If locktime is set and it is for more than 10 KMD, Rewards is accruing
so as long as the wallet you use implements the spending of Rewards, you are fine.