I don't really struggle to remember to test and bolus. It's fairly automatic nowadays - it's built in, before I eat, I have to bolus and the pump asks me to test before I bolus. It's pretty difficult for me to get away from the pump, or at least too far away as the cannula's quite short.
Are you really forgetting to bolus? Or are you making a concious decision not to bother. Because you have a pretty decent sized reminder, the pump, on you, all the time. Most pumps can be set to alarm reminders. Those reminders can be a prompt to test or bolus or to change set. If you google "how to set a reminder on a [use your pump name]" hopefully you'll get lots of tips on hope to set alarms on your pump.
You could set alarms to test, bolus and change set on your phone.
To make the behaviour automatic you need to make it as easy as possible for yourself. So are you the kind of person who has the same thing for breakfast everyday? If so, make sure you know the grams of carbs in your breakfast before you go to bed, you have your test kit on your bed side table as you go to sleep, the alarm on your phone is set with the words "test blood sugar". Then you have every thing you need to test and bolus for breakfast. Set yourself a goal to test and bolus for breakfast every day in a week. Then tests and bolus for breakfast and lunch everyday next week. Once you've done it everyday for two weeks it should be becoming habit. Once it's habit, that's the thing that makes it automatic.
Have a think about what are the things that make it hard for you at the moment. Is it knowing the carb value of your meals? You can download the app myfitnesspal and use that to carb count your meals. Is it finding time to test and bolus? If you have a spare hand and time to eat, then you have time to test and bolus. You can make it a bit easier by keeping a spare test kit in your kitchen - pop it in your cutlery drawer and that will make forgetting rather difficult. Is it finding a place to test? Are you uncomfortable having people see you testing or getting you pump out? If you're in work your work should give you somewhere like the first aid room or just a quiet room to test if you ask, but remember that no one will notice you testing, it's a tiny little thing and no one will see it, you can quite happily do it anywhere, surrounded by people without anyone giving you a second glance.
I'm not very good at changing my set every 3 days, I tend to just let it run until the reservoir runs out. I'm on about 30 units a day, filling the tube and cannula is about 10 units so a 180u reservoir lasts about 5 days. It's not recommended. If I notice problems with insulin working on day 4 or 5, I'll change the set but that doesn't happen very often. I don't have problems with my cannula site healing. So I'm not particularly motivated to change site more frequently. It's not recommended, but it's not doing me any harm. I'm not forgetting to change sites, I make the concious decision not to.