As long as you don't overheat the flat tire (by driving on it too far, and/or too fast) and the cut is in the tread area, it can be fixed. Correct fix is an inside patch, using a special combination patch/plug. The tire ends up as good as new. It doesn't work with a sidewall cut, and it doesn't work if you have driven the RFT in a low pressure condition, long enough to cause damage from heat. If you get a low tire warning, check the pressures. If it is only down a few psi, no big issue, get to a tire shop. If it is very low, you need to go slowly enough not to get it hot, until you get to a tire shop that can fix it. An on board compressor and a temporary plug kit can extend that range.

I definitely wouldn't be changing wheels and tires just as a preventative measure. If you have the space, and a jack to take along, carrying a winter tire as a spare isn't a bad idea. It is just that there probably isn't anywhere to put that tire and jack.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue