Go/run like clockwork = it happens exactly as planned and without problems.

• The party went like clockwork.
• Everyday he comes here for a cup of coffee at 3.00 p.m like clockwork.
• He soon had the household running like clockwork.
• The journey to the tourist destination went like clockwork.

Start from scratch = go right back to the beginning and start again.

• He built his own computer company from scratch.
• My template got deleted so now I have to write the whole report from scratch.
• Building a home from scratch can be both exciting and challenging.

Once and for all ( or once for all) = finally and definitely.

• The government should do something to solve the problem of illegal drugs once and for all.
• We have to resolve the matter once and for all.
• We have to decide , once and for all, whether we want to ask Dad for money.
• The president is hoping to silence critics once and for all with the latest law.