Best bet is to buy the largest QUALITY SSD you can reasonably afford while not sacrificing quality of other needed system components. What is a "small" drive today will be a useless drive tomorrow. What is fast today will be marginal at best in 3-5 years for most, and will be totally unacceptable for bleeding edge game-play in 1.5 - 2.5 years. That's worthy of consideration.
Cheap SSD's also degrade much faster, and turning your computer on only to discover your boot drive is dead is not at ALL convinent.
I have a large number of large programs on my machine, but I rarely install new software. I have been using personal computers since 1980 though, and know what I will use and what I will not. I also always uninstall programs if I know I do not want them, which saves a LOT of space and keeps things running fast.
Samsung and Intel drives are very reliable drives. I have both, and they have been serving me without a single issue for quite awhile. My Samsungs are the old 840 Pros, and my one Intel is an old x25 series drive. All 3 drives are still reporting very healthy through the manufactrers SSD management tools.
I do also credit the use of high quality power supplies that are LARGE ENOUGH to adiquitely power ALL of the components in my machines for the fact that I don't experience "break downs." This is often overlooked. When people load up machines with lots of drives and power-hungry video cards at great expense, but power then with a supply that's under-rated for the demand of the system, they smoke expensive gear and create damages can be a nightmare to diagnose, even after the power supply is replaced, because things like motherboards can have portions that are intermittently functional and are the root of what may cause another component to look faulty, or worse yet, be DAMAGING that component every time it is swapped for a new part.
SSD's don't draw a lot, but are pricey and are suseptable to damage in an underpowered system.
One last thing to consider regarding using multiple drives is that, you can only plug in so many drives before you run out of available ports, so, going with a larger single drive to start, especially for those that don't NEED to spend a ton of extra cash to get a 6% overall system performance gain tends to make the end-user much happier with their machine and the price they paid for it for much longer. I say this not only as an end user myself, but also from the professional standpoint of a former independent computer shop tech that designed all of the "standard custom built" pc configurations that we sold as base models, and also the specific component upgrades that customers could specify additional upgra should they wish. Those base models and offered upgrades HAD to be rock solid, or we'd have been like the other shops that would come and go in a year or 6 month's time because they were always trying to figure out why there customer's brand new machines were coming back.
No-one gets much productivity or fun out of a computer that always has gremlins. FACT. 😉