Most of the guidelines in menswear exist because of practical reasons that have proven useful reference points over time. Things like “the more polished your shoes are, the more formal they become” make sense and are reliable, easy positions to make decisions from when choosing what you’re going to wear. Guidelines like this are unlikely to become dated as our response to the shine of a surface is inbuilt, rather than a creation of culture.
Where guidelines become less relevant over time is when broad societal norms evolve and change. One of the most obvious is the general relaxing of the “no brown in town” guideline, to which societal mores have softened. Years ago, brown shoes were reserved strictly for rural areas (farm life or time spent in the country, generally) and to wear them in the city was cultural suicide. Over recent years, polished, well-made brown calfskin shoes have become acceptable in even the most professional environments, particularly when worn with a blue suit. Black will always be more formal, but the old guideline has generally given way to the more relaxed professional world that non exists.
In the same category is the old American phrase “no white (trousers) after Labor Day”. The phrase came about as Labor Day (early September) marks the turn of the seasons, from the heat of Summer to the chill of Autumn in the northern hemisphere. The brightness of white trousers was deemed only to suitable for hot months and, therefore, inappropriate for the more somber, colder months. You can see how the conclusion could have been reached, but it’s not the right one, at least not for modern times.
These days, white or off-white (bone, ivory etc) trousers are usually my first preference each day when deciding what to wear, regardless of the time of year.
In summer, slim-cut white trousers with brown tassel loafers or even more casual Miserocchi loafers with a blue or navy shirt is as close to the perfect casual summer outfit there is. Alternatively, a more traditional/English cut (read: slightly wider leg with less of a taper) works well with lace up oxfords or brogues.
In Winter, the brightness of white/off-white trousers helps to offset the gloom of cold weather but still harmonises with the often found starkness of Winter’s surroundings. Think reasonably slim cut white trousers over a pair of Edward Green “Galway” boots, a thick roll-neck sweater, navy cashmere overcoat, with a scarf and leather gloves. With a change of tone from white to ivory (like Fox Brothers Cricket White Flannel) you bring in real warmth to the trousers, if you feel that white could be too severe (additionally, the muted texture of flannel softens any outfit and is always worth bearing in mind, regardless of colour).
The versatility of white/off white trousers is often overlooked, but they are among the most versatile trouser colours, purely from the amount of colours that can be worn with them. Whilst Navy and Grey are the 2 staple colours of your wardrobe they still have their limits with the other colours they can be worn with harmoniously. White can be paired with any colour of shirt/jumper/jacket (other than all white, unless you’ve joined a cult). If you have an item in your wardrobe which you find hard to pair with any other trousers, you’ll often find that it will work easily with white.
It takes a little getting over the contrived and now outdated Labor Day cliche, but if you make the effort to build a collection of white and off-white trousers in different weights and cloths for the seasons, you’ll find yourself going back to them constantly.