In case you need to monitor certain columns for updates, use:

CREATE TRIGGER tr1 ON Customers

FOR UPDATE AS

IF ((SUBSTRING(COLUMNS_UPDATED(),1,1)=power(2,(3-1))+ power(2,(5-1))) 

AND (SUBSTRING(COLUMNS_UPDATED(),2,1)=power(2,(2-1))))

insert into audit (date_updated, event_desc) values (getdate(), 'Columns 3, 5 and 10 got updated.')

go

You can get more details from virtual 'inserted' table:

declare @newcol3value int

set @newcol3value = (select col3 from inserted)

insert into audit (date_updated, event_desc) values (getdate(), 'Columns 3 (' + @newcol3value  + '), 5 and 10 got updated.')