Automation
It comes by many names: paying yourself first, spending the rest, or preauthorized purchase plans, but the idea boils down to the same thing. Automate your saving and investing so it's easier to stick to your plan and invisible to you. With mutual funds at Tangerine or TD you can pull money from your chequing account on a regular basis (weekly, biweekly, or monthly) and have it invested in your fund(s) of choice. For ETFs you may have to purchase manually after the automatic transfer of cash is made.
I quite recommend automatic contributions to your TFSA, RRSP, and then non-registered if those fill up. Remember though that you have limited room in your tax-sheltered accounts. For automatic contributions I would ensure that the monthly contribution is less than 1/12 of your annual contribution room. That may mean adjusting your RRSP contributions every year, and your TFSA ones each time the government adjusts the annual contribution room.
Automatic contributions are an often-recommended and highly effective way to stick to a savings plan, and the behavioural reason is clear: our spending is often like a gas, expanding to fill the available volume. If your savings and long-term investments are taken out of your chequing account automatically as your paycheque arrives, you will quite likely find a way to live on the remaining amount. If you cut back on frivolous spending as part of your financial plan, you may not even notice the change in your quality of life as some spending may have been unconscious. When you try to put away whatever is left at the end of the month instead, you may find that unplanned or unconscious spending has eaten into your savings.
Even if you don't want to go into full automation – for instance if your HR department is staffed by flying monkeys who routinely delay posting your paycheque, and any automated transactions from your bank account may risk a bounced cheque or overdraft – you can semi-automate through calendar reminders to keep you on plan. I love Google Calendar for its ability to quickly create recurring events; the big benefit though is that I can also set them up to send me an email reminder. I can paste into the description field instructions to my future self. Some good reminders to set up include an annual rebalancing, to check your online statements at tax time, to contribute to your accounts. Here are some sample calendar reminders that you may find useful:
Most of those dates are completely arbitrary and up to you. Try to make them fit your own life and plan: it's not super-critical which day of the year you rebalance as long as you do it regularly – roughly once per year is just an approximate rule-of-thumb. If your work and family keeps you busy near the new year, then put it in the late summer when things are calmer; I like to do it at tax time when I will have all my statements out anyway and my mind is fully in money mode. Use whatever works best for you and will make it easiest for you to stick to your plan.
Oh, and despite the media blitz that happens every February, RRSP “season” isn't really a big deal. You can contribute any day of the year, the deadline is just for whether you can claim it against one year's taxes or the one following. A more successful approach in my mind is to ignore all that last-minute stress, and go with a steady monthly contribution year-round. When you're 75 and spending that money you'll care whether it's there at all far more than whether the tax deduction was taken a year later. You can even fill out some forms with your employer to reduce the amount of tax taken off your paycheque each period so you don't have to wait for your refund to come in at the end of the year – which will also help remove the temptation to spend the refund.
With a good process in place – automation, reminder/summary sheets, rebalancing spreadsheet tools, calendar reminders, and uncomplicated choices and allocations – you hopefully won't need to work too hard to retain any of the specialized knowledge here. You can do all the hard stuff and make the major decisions while it's all fresh in your mind and the book is in front of you, then set it up to be as easy as possible for your future self to follow-through and stick to your plan.
Set up a plan, put it into practice, and stick to it! Keep it simple yet effective: an emergency fund for the short term and just four funds will cover your bases for the long term. Keep your costs reasonably low. Rebalance when necessary, but not constantly. Automation can help you stick to your plan.