Use a own instance for SqlServer Express?

Question

I'm currently developing an application that needs to store data in it's on database, I'm currently using SQL Server Express 2005 with Advanced Services (because we need full text search capabilities).

Local company lore says there have been all sorts of strange problems some years ago when two products used MS SQL Server with the default instance and they had interesting times cleaning everything up into making each application use a named instance.

As I can't remember the exact problems they had ... is it advisable for an application that has to run in a stable way without interference from some other application to have its database in its own named instance? If so, why? What additional isolation does that grant me as opposed to attaching the database to the default instance (or even use a watchacallit - user instance? - where you specify the mdb file location in the connection string).

Update:

The main concern I have is not performance/CPU - I'm talking about an application that manages Persons/Guests at the front desks of large organizations, think a hotel for example. I think even SQLite could easily handle the amount of data I need (disregarding some features like fulltext search).

My main concern is Customers installing stuff that interferes. From Mitchell's Answer and John's comment from it I think it is advisable to stay in a named instance - but if you have more reasons for that, please voice them.

Answer 1

A few things.

1. Using attached databases (User instance dbs) are a royal PITA for administrators to manage, as they must be attached to be accessible from SSMS and more.

2. Putting individual applications on their own named instances of SQL Server will create individual processes for each application, isolating resources and memory spaces for each.

Is it really necessary for each application to have its own instance of SQL Server? No, I would say typically it is not, unless it is truly 100% mission critical, however, if it is that critical, I would be surprised if it is running SQL Express.

I would recommend though from a maint. perspective that you use a standard database, rather than a user instance.