rent increase etiquette

General Discussion

i was hoping some of you can help me out here. Basically I have a tenant who pays semi-regularly on time but i want to increase the rent because is it too low considering what similar houses on the street are. Yet, i went round last week to see her and over the last few months she has done improvements to the property eg new wallpaper etc.
Is their etiquette involved here or should i just disregard the improvements and put the price up anyway?
For the record I dont mind losing this tenant...

much appreciated

Mike