One-off actions and easy habits

I can be lazy, so I like the kind of frugality where just one initial set-up action is needed, with maybe the occasional review.

Some examples of one-off actions that I have taken:

• Getting a water butt for the garden several years ago.  I like this because it is environmentally friendly, while also providing free water, enough for all our gardening needs. (Though my mother would say that I don't water the garden enough, so that may be why....)
• Working out the cheapest way to pay regular bills - for most bills this is by monthly direct debit- and setting up payment accordingly. I first did this many years ago, and do now review the situation every so often.
• Putting dryer balls (mentioned in an earlier post) in my tumble dryer.
• Fitting water-reducing devices into our lavatories years ago, which saves a considerable amount of water.
  

We also have some habits which are so simple, and so ingrained, that they are now almost automatic:

• Using second-class stamps for all non-urgent post
• Putting the end of a loaf of bread in the freezer for later use as toast, before it goes stale
• Using plastic carrier bags as kitchen bin liners
• Putting vegetable matter, tea leaves, and coffee grounds onto the compost heap
  
• Contributing a proportion of our income to our pensions, whenever we are paid, at the same time we save money for tax.  (This doesn't happen automatically, now that we are both self-employed.)

Many of these actions and habits won't result in large savings, but the effort involved is minimal, and over the years these small things add up.  What am I missing?  What habits or one-off actions have you taken?