You can bring your history with you. Export it, map your columns once, and every day you logged comes across dated as the day you logged it. It is free and takes about a minute.
Clean, fast, on every platform, and its data export is more thorough than most.
The free tier is tightly capped, which is the most common thing people mention about it. And while it exports well, there is nowhere to take the file: it does not read a CSV back in.
Export menus move around. If these steps do not match what you see, look for anything that says export, backup or download, and pick the CSV.
Habit completion history, and any numeric habits as numbers rather than as ticks. You choose per column whether each one becomes a new habit or joins one you already have.
Habitify's reminders, its notes on individual check-ins, and any habit archived before the export was taken. Set your reminders up again here once the history is in.
The export sits next to the import, on the same free plan. Everything you log comes back out as a CSV whenever you want it, including your medication history. That is the whole reason this page can exist: nobody should be stuck somewhere because their record is.