Diagnosed LADA in late 2014. I was prescribed Metformin initially. Due to my fixed income and inability to shop around as much as I'd like, I haven't been able to change my diet the way I want to. I am mindful of carbs but still average between 120-200 grams a day because the foods I can afford have those amounts of carbs in them. This meant my A1C levels stayed consistently high as the metformin didn't do enough on its own. I was prescribed gliclazide and for a while, I was doing excellent with my diet and med combo. I had dropped to 6.4 from being in the 7+ range.
I believe the gliclazide accelerated my condition. By June 2016 I was on basal (Toujeo) insulin alongside Metformin and a double dose of gliclazide, as my levels had gone from good to bad again (7.5). I gained weight like crazy, had massive fluctuations in my glucose levels and I couldn't find the right balance for my diet. No two days produced consistent results. I had to eat a lot when I exercised because I hypo'd super fast, but without the gliclazide I skyrocketed at every turn.
At the beginning of this month I got started on bolus (Novorapid) insulin and dropped the gliclazide. I am still using Metformin (I have no side-effects from it and it does help in my situation). My body's own insulin production has dropped significantly, as the gliclazide was making it work overtime to produce insulin, but I am finally getting stable values throughout the day. Stress and insomnia do affect me, as they would anyone else, but I have not gained (I initially lost 1kg) weight and I am able to eat much smaller meals because I can properly adjust my insulin to what I eat.
I regret having been on gliclazide for so long. The Metformin is relatively harmless to your pancreas, but the gliclazide forces whatever beta cells are left to produce extra, and it wears them out faster. I spent an unnecessarily long time with too high of an A1C, suffering rollercoaster levels and being forced into a diet I didn't want to be any worse than it already was.
My recommendation is to listen to yourself and your body. This disease is incredibly personal and while you can take info from our stories and take what you need, ultimately we can't decide for you. If you feel you are losing control of your condition because you do not produce enough insulin for your diet, then it's time to switch to insulin. I strongly advise to turn down meds like gliclazide because I haven't really found anyone for whom it worked more than a few short months, myself included, before it turned into a rollercoaster hell. In the end, a LADA/1.5 will become insulin dependent, and if your oral meds aren't cutting it anymore to get the control you need, it's time for insulin. When that point is reached, is up to you!