What is best practice for confirming success of Update queries
You could query before and after looking for the particular conditions you are wanting to update. 

For adhoc queries it's a good idea to run the query as a select statement using the same where clause before running as an update statement. 

The update should update exactly the same rows select returned unless the data has changed. 

create table #test ([id] int identity (1,1), [status] varchar(50) )

insert into #test VALUES ('COMPLETED')
insert into #test VALUES ('FAULTED')
insert into #test VALUES ('COMPLETED')
insert into #test VALUES ('FAULTED')
insert into #test VALUES ('FAULTED')    

select status
from #test 
where status = 'FAULTED'

select count(*) 
from #test 
where status = 'FAULTED'

update #test 
set status = 'FAILED'
where status = 'FAULTED'

select count(*) 
from #test 
where status = 'FAULTED'

select status, count(*) 
from #test 
group by status