Do you ToList()?

Question

Do you have a default type that you prefer to use in your dealings with the results of LINQ queries?

By default LINQ will return an IEnumerable<>

Answer 1

ToList always evaluates the sequence immediately - not just in LINQ to SQL. If you want that, that's fine - but it's not always appropriate.

Personally I would try to avoid declaring that you return List directly - usually IList is more appropriate, and allows you to change to a different implementation later on. Of course, there are some operations which are only specified on List itself... this sort of decision is always tricky.

EDIT: (I would have put this in a comment, but it would be too bulky.) Deferred execution allows you to deal with data sources which are too big to fit in memory. For instance, if you're processing log files - transforming them from one format to another, uploading them into a database, working out some stats, or something like that - you may very well be able to handle arbitrary amounts of data by streaming it, but you really don't want to suck everything into memory. This may not be a concern for your particular application, but it's something to bear in mind.