Occasionally, Schmidt-Cassegrain scopes need collimation. It is not that difficult to do. The secondary collimation screws are hidden underneath the circular plate that covers where the secondary mirror is located. I have personally done this with a C8 OTA, no problems. I hear some people who have SCT's say "I bought it because it will never need collimation." Sadly, this is not true.
A Maksutov is much more difficult to collimate. I bought a 4SE last year, and fortunately the optical alignment was in good order. When I went online out of curiosity about collimating a Maksutov, I got discouraged quickly.
You might want to think about buying a scope without a computerized mount. That will save lots of money. Regarding Dobsonians, if you can get a 6" f8, that would serve your needs well. At f8, the collimation should hold well over time. Faster Dobs (lower F ration) are the ones that need frequent collimation adjustments. At f8, you can achieve a high magnification for viewing planets. I have observed all 110 Messier objects with our 6" f8 Newtonian that had just a clock drive (RA tracking motor). The scope's mount has no computerized functions, as I used it in the 1980's and early 90's when normal people could not afford such luxuries.
If you get a mount with electronics, please know that these are battery hogs. A set of ordinary batteries will only last through three or four observing sessions. On the small computerized mounts which I use, there is no warning of "Low Battery." The mount will act oddly, then quit altogether with no warning when the batteries get low. This is really disconcerting, especially at an outreach event. So for our scopes that require power, we use special power supplies for the scopes. Beginners often ask what accessories to buy, and a Power Tank of some kind should be high up on the list.
Best of luck, and clear skies to you this summer!
Edited by ShaulaB, 16 June 2019 - 01:05 PM.