architecture web-applications web-services

When should a web service not be used?

Using a web service is often an excellent architectural approach. And, with the advent of WCF in .Net, it’s getting even better.

But, in my experience, some people seem to think that web services should always be used in the data access layer for calls to the database. I don’t think that web services are the universal solution.

I am thinking of smaller intranet applications with a few dozen users. The web app and its web service are deployed to one web server, not a web farm. There isn’t going to be another web app in the future that can use this particular web service. It seems to me that the cost of calling the web service unnecessarily increases the burden on the web server. There is a performance hit to inter-process calls. Maintaining and debugging the code for the web app and the web service is more complicated. So is deployment. I just don’t see the advantages of using a web service here.

One could test this by creating two versions of the web app, with and without the web service, and do stress testing, but I haven’t done it.

Do you have an opinion on using web services for small-scale web app’s? Any other occasions when web services are not a good architectural choice?