We are often told it is the person who makes the picture, not the gear. For listening to the wrong person, I stayed stagnant in photography for years because if you haven't gotten to find the right tool, how are you going to make good pictures? Henri Cartier-Bresson may use one camera and one lens for all his work but he is a master at this craft. Fact is, he can be using a disposable camera and still churn art. So, leave zoom lenses aside to set aside distraction as one focal length will make you a better photographer.
28mm
Ultra wide-angle
A wide angle together with relatively large aperture does make this the only lens you’d ever need. Unlike cream of the crop lenses, this has small dimensions, does not much weight and nails focus just as well. One thing to have in mind is that composition might pose as a challenge unless you are mostly into indoor or landscape shots. It is one I’d recommend for the more seasoned photographer.
35mm
Wide-angle
This is smacked right in the middle and also a personal favourite because it is perfect for almost every situation. Admittedly a little tight indoors otherwise there’s no need to take a step back when you stumble across an interesting subject. One reason to choose this over an L version is image stabilisation. If you do not like lugging a tripod, this is a feature that’s very much appreciated when shooting film at night. Though not recommended, I’ve yield usable images shooting at a tenth of a second. At 335 grams, it is about the weight of the 28 which will get you through the day without a neck ache.
Downsides? Not that it is large in size but the 35 mm f/2 isn’t exactly small and it is the priciest in this bunch.
40mm
Standard
The nifty fifty can be a tad tight so a 40? No other lens is able to match this one for size and weight. Furthermore, there is no need to baby this lens as they retail at a very affordable price point. The only niggle I can say is its focusing speed isn’t the quickest as the STM line of glass places importance in video work. That aside, those who are after bokeh may steer away because its maximum aperture of f/2.8 which is narrower than most prime lenses.
Lenses of such can be had for reasonable prices today if you decide to pick them up during promotional periods, they can be sold off for pretty much the same. I say go for it as it is a shame for a concern like this one to keep anyone from taking great photographs that lasts a lifetime.