"Don't Break The Chain" can be dangerous on its own.

Whenever I do break the chain, I feel unmotivated to start the chain again (especially if I've done a good job, because it seems overwhelming to pick it up again from the start of the chain).

I've had to move on from Don't Break The Chain to being positive about making consistent progress.

I would say Don't Break The Chain is great for a fixed-length, short-to-medium-term task, rather than instilling permanent habits.

You can make your chain more coarse than daily. For example, for me it's a lot easier to commit to doing something 5 days a week rather every single day so my chain links are measured in units of weeks rather than days. You don't need to beat yourself up about missing a day or two here and there.

Agreed. The solution I like is http://beeminder.com/.

I use a variation of this technique. I spend X minutes doing Y. Where X is 5 minutes. The 25 minutes of the Pomodoro is too long to focus on one thing. I have a very very short attention span and I found 5 minutes to be the optimal timebox for me. Anything longer and I get bored. Now I have clock which doesn't increment in minutes but 5minute units. It's the only way I can make sense of the passage of time.

At the end of the timebox I do a 30sec review where I assess how I executed the task. Did I spend most of the time searching for information and organising material or did I spend it purely executing. I find with highly skilled people they spend most of they're time executing. If I spent most of it searching for stuff, I'd mark it as a delay due to organisation, if I was searching on how to do the task I would mark it is 'upskill', then I'd move onto the next thing. After a few hours patterns start to emerge around similar tasks. If a lot of related items were marked 'org' I'd then exploit them for automation or create them as templates for resuse. All the 'upskill' marked tasks would be condensed into a learning task at a more convenient task. The idea around all of this was to progressively become more organised and more skilled so that when performing a task, I would purely be executing and not faffing about.

It's a bit convoluted but it is a system that has worked terribly well since late last year and it's made me twice as productive at work, and smarter at what I do. There are times though where I wish I could be like people around me who are able to focus on thing for half an hour or more but we all have to play the hand we've been dealt and mine is a chronic lack of focus.