Grammar Focus

'USED TO' for past habits
* We use 'used to' to talk about past events which we no longer do. We only use it to talk about the past; there is no similar expression for the present.

'I studied French, but I don’t anymore.' → 'I used to study French.'
'In the past I smoked, but I don't now.' → 'I used to smoke.'

Note: after 'used' to we always use the infinitive.

* Asking questions using 'use to'

'Did you use to watch Mickey Mouse?'
'Did you use to like school?'

* Answering 'use to' questions

'Did you use to wear a school uniform?'
'Yes, I used to wear a horrible uniform!' 

'I didn't use to wear a uniform'. or 'I used not to...'

Using 'WOULD' instead of 'USED TO'

* We use 'would' when we want to talk about how often a past habit happened. It can have the same meaning as 'used to'. 

'I used to go swimming twice a week.'→ ' I would go swimming twice a week.' 
Note: Both of these sentences have the same meaning.

We can use 'would' instead of 'used to' when a time is mentioned:
'When I was young, I used to visit my grandmother every summmer.'→ ' When I was young, I would visit my grandmother every summer.' 

If the sentence is not about a repeating habit/action, or does not include a time expression, we can not use 'would':
'I used to play piano.'→'I would play piano.'

It is more natural to say:
'I used to play piano. I would practise every day.'