It really depends on how you want your pigs to look.
The breeder may keep his/her breeding animals trimmed very short (and only keep two or three show pigs with any length of coat). If so, yes, a weekly check for tangles is absolutely fine.
But the whole point of you getting a Texel or Alpaca is that you want a longhaired pig! If the coat is trimmed so that the pig can keep himself clean (very short around the hind legs/privates and “Dougal Dog†length around the rest of the body so the hair doesn’t trail on the ground) you will need to brush/comb him at least 3-4 times a week and check for knots. It only takes a few minutes!
Two things to bear in mind.
If these are good quality Texels/Alpacas from a serious breeder (and not just a backyard breeder churning them out because they can sell them for higher prices than short haired pigs) their coats will grow at approx. one inch per month. Therefore, logically, in two months the pig will have grown 2 inches more coat and that is definitely long enough to get very tangled. Realistically a monthly clip is what is needed. Again, it really doesn’t take long; I find it very much easier and get a neater result by trimming my longhaired pigs after a bath.
Secondly, a neatly trimmed ‘Dougal’ style pig can look really cute …BUT… it is up to the pig’s friends (and not you) whether or not he stays that way. Some pigs just take great delight in chewing their friend’s coats off…so you could have a longhaired and never really know about it!