Welcome to the forum!
Text can be scaled at will, without losing clarity -- as long as it remains as text or path. If it becomes rasterized, it will pixelate upon scaling. I'm a little fuzzy on this next point. But I have the understanding that most of the text that you find on the internet, is in vector form, if the text is still in its original file, and has not become rasterized (via file conversions or exports or something). Unless it's a poorly made font, the letters will not overlap when scaled.
It is possible to set text to have the same stroke width, and other objects to have different stroke widths. However, the only way I know to do it, will mean that all text will have strokes (or else you would have to manually remove the stroke, if you didn't want it on some particular text).
1 -- type some text
2 -- give it whatever style you want (style includes fill, stroke, stroke width and color, opacity, among several more options)
3 -- leave it selected
4 -- double-click on the Text tool button (this opens Inkscape preferences directly to the Text tool controls)
5 -- click "This tool's own style"
6 -- click the bar titled "Take from selection"
However, that only affects new text that you type. If you mean that you want to add a stroke to existing text, as long as it is still text (not converted to paths or rasterized) you can use Edit menu > Find/Replace. That would allow you to select all the text in the file, and add the stroke all at once. However, you may find, if there are different sizes of text, that you need different stroke widths for different sized text. It depends on the font and any kerning it might have (and probably some other things that don't come to mind at the moment) whether adding a stroke might make the letters overlap. So it might not be feasible to change all the text at once, if you need to assign different widths to different text.
Also, this is very important for scaling objects with strokes. On the Selection tool control bar, the 4th button from the right causes the stroke width to remain proportional when scaled. That means the the stroke width gets smaller when scaled down and wider when scaled up. So if you must scale the text, make sure it's enabled. If it's not, then the letters might overlap when scaled down. It's tiny, but the button looks like this:
The Find/Replace dialog has changed quite a bit since this manual info was written.
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Select.html#Select-Find The only current tutorial I know about is part of a series of articles/tutorials in
Full Circle Magazine. The problem is that I don't know any easy way to search them.
If you want to try, here are links I have, to the 6 special editions, which contain only Inkscape tutorials:
Volume 1 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-one/Volume 2 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-two/3 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-03/4 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-04/5 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-05/6 -
http://fullcirclemagazine.org/inkscape-special-edition-volume-06/In any case, if you don't want to search those, the dialog is fairly self-explanatory. And if you need help, just ask
For other objects, it's a similar routine. If you're drawing new objects, then you can set the style of whatever tool you use to draw them. If they are existing objects, and you can find some SVG attribute or value (includes style) which is similar to a particular group or set of objects, you can use Find/Replace.
(If anyone knows of a better way to search Xav's series, I would love to know!)
