One thing worth doing it to fit a power 6 to 7V Zener diode clamp to the +5V rail. Most TTL devices can handle up to 7V for a short period.
Also there is something else, if a logic board of any kind is powered by a power supply, and is separate from it and not hard wired to, there can also be the chance of something worse, a reverse polarity accident. In this case the power Zener clamps the voltage to less than a volt when it conducts in the reverse direction. A series fuse with it helps as it will blow when the zener conducts in either direction. When I have boards with many TTL IC's on them (that I make myself) I typically have a device, one example is the 1N6267 that I use on my Pong boards with 66 TTL IC's:
Another example happened in the Hero Jr Robot, it was powered by two 6V get cells that ran in series, but people installed 12V types by mistake, this often killed a lot of components, including the rare Votrax SC-01A speech chip, I fixed this risk with a Power Zener & a fuse:
www.worldphaco.com/uploads/SAVING_HERO_Jr_FROM_HIGH_VOLTAGE_and_REVERSE_POLARITY___Hero_Jr_Radio_Board..pdf
But, like the set of steak knives, there is more:
One issue with an smps, but it depends on the design complexity, is that some of the cheaper ones can have failure modes where the output voltage can jump up. For this reason, unless I inspect the design I seldom use them. I trust the National Semiconductors LM309k +5V regulator (still available from major supplies under the name LM309k-steel, if on a heatsink they are good for over 1A). They are also available in a mil spec version on the bay. The reason is, I have never seen one over-voltage its output yet as a failure mode (they practically never fail in any mode due to the internal protection systems, and there is negligible noise in its output). I would rather not worry about the efficiency issues over reliability & safety for the devices they power, unless the thing was battery operated perhaps. Some replacement switching modules have been made to replace TO-3 cased & TO-220 cased regulators,with the same footprint, but I would not go anywhere near them with a barge pole.
I recognized the genius of National's LM309k back in the late 1970's, by then they already had nearly a decade of reliable service and over the last 50 years, I have not been disappointed, even once.The manufacturers were so confident they called them "blowout proof", though they probably should not have, that is like saying the Titanic was unsinkable and tempting fate. Whether any clone versions are as good, I could not say.
I bought a box of them from Surplus Sales in Nebraska and use then in restorations, not to replace failed parts but if the originals are badly corroded externally, or for my own projects. I trust these over any smps, but it is just my opinion that I offer here.