Notification Rules

Hi All

P2P cycle in my organisation is

Create PR  > Approve PR > Create RFQ > Enter Surrogate Quote for RFQ > Award Approval > PO Creation > PO approval

So basically we have Approval notification for

1. PR approval notification 

2. RFQ Award Approval

3. PO Approval

Now the business requirement is , when ever in the approval notification is pending for approval  N number of days there should be another notification fired to User W .

How cab we achieve this.

one way is to do through alert. Do we have any other way ?

Thanks

Pankaj