Whether Logfile Shrinking is good or bad one for Performance in SQL? I am using SQL Server 2008 R2 database and on our SQL Server instance we have more than 70 databases. In a few databases I can see that the transaction log file size is more than 10 GB. I am shrinking the Tlog file size on a daily basis using the following script:

USE ABC;
GO
-- Truncate the log by changing the database recovery model to SIMPLE.
ALTER DATABASE ABC
SET RECOVERY SIMPLE;
GO
-- Shrink the truncated log file to 1 MB.
DBCC SHRINKFILE (ABC_log, 1);
GO
-- Reset the database recovery model.
ALTER DATABASE ABC
SET RECOVERY FULL;
GO


Is there any recommended way to shrink the transaction log file size?
Shrinking of log file ON DAILY BASIS like one you do with query you posted is seriously bad and you should NOT do that. The main reason is that after you have shrinked the file it will grow again when new transaction comes and since INSTANT FILE INITIALIZATION is not there for Log files, its only for data files, when log file will grow DB engine will actually have to zero out space to write information so instead of overwriting free space it has to be overwritten with zero values (0×0) and then information can be written. This process takes time and thus delays processing of query

Nice explanation has been done in This link

Please note that instant file initialization is applied to some extent for Tempdb log files even though this is correct you should not shrink tempdb log files on daly basis.

A more simple thought, why to shrink if space has to eventually grow when log informations will be written and log will grow. Its a bad practice, internet is filled with advise not to shrink data files but shrinking log file is equally bad 

EDIT: Needless to say( as already pointed out) you are breaking chain of logs by changing recovery model to simple. You loos epoint in time recovery. If point in time recovery is not required kep recovery model of database as simple and log truncations would be handled by DB engine if something is not holding logs and need it in transaction.