It depends a little on how much data is building up and if its causing an issue. In a high throughput distribution db you can have the replication cleanup jobs running every few minutes to keep the data levels low (assuming the distribution agent is doing its job).
With low data levels index fragmentation isn't a problem.
Very min data is retained in the distribution database. Recently we are continuously experiencing blocking(>30 mins) on distribution server which in turn causing latency. Trying to figure out exactly what's causing this issue?
the most common causes of blocking are with distribution clean up job blocking the update statements on msdistributin_history table and the rest related to msrepl_commands table.